diff --git a/homeassistant/components/bom/sensor.py b/homeassistant/components/bom/sensor.py
index 5ecd9c1009f..8386409d3ea 100644
--- a/homeassistant/components/bom/sensor.py
+++ b/homeassistant/components/bom/sensor.py
@@ -19,6 +19,7 @@ from homeassistant.const import (
     CONF_LONGITUDE,
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
+    LENGTH_KILOMETERS,
     SPEED_KILOMETERS_PER_HOUR,
     TEMP_CELSIUS,
     UNIT_PERCENTAGE,
@@ -74,7 +75,7 @@ SENSOR_TYPES = {
     "swell_dir_worded": ["Swell Direction", None],
     "swell_height": ["Swell Height", "m"],
     "swell_period": ["Swell Period", None],
-    "vis_km": ["Visability km", "km"],
+    "vis_km": [f"Visability {LENGTH_KILOMETERS}", LENGTH_KILOMETERS],
     "weather": ["Weather", None],
     "wind_dir": ["Wind Direction", None],
     "wind_spd_kmh": ["Wind Speed kmh", SPEED_KILOMETERS_PER_HOUR],
diff --git a/homeassistant/components/buienradar/sensor.py b/homeassistant/components/buienradar/sensor.py
index ddaeec94228..de7dd04a48e 100644
--- a/homeassistant/components/buienradar/sensor.py
+++ b/homeassistant/components/buienradar/sensor.py
@@ -28,6 +28,7 @@ from homeassistant.const import (
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
     IRRADIATION_WATTS_PER_SQUARE_METER,
+    LENGTH_KILOMETERS,
     SPEED_KILOMETERS_PER_HOUR,
     TEMP_CELSIUS,
     TIME_HOURS,
@@ -77,7 +78,7 @@ SENSOR_TYPES = {
     "winddirection": ["Wind direction", None, "mdi:compass-outline"],
     "windazimuth": ["Wind direction azimuth", "°", "mdi:compass-outline"],
     "pressure": ["Pressure", "hPa", "mdi:gauge"],
-    "visibility": ["Visibility", "km", None],
+    "visibility": ["Visibility", LENGTH_KILOMETERS, None],
     "windgust": ["Wind gust", SPEED_KILOMETERS_PER_HOUR, "mdi:weather-windy"],
     "precipitation": ["Precipitation", f"mm/{TIME_HOURS}", "mdi:weather-pouring"],
     "irradiance": ["Irradiance", IRRADIATION_WATTS_PER_SQUARE_METER, "mdi:sunglasses"],
diff --git a/homeassistant/components/darksky/sensor.py b/homeassistant/components/darksky/sensor.py
index c2f6ee83396..d372811edd8 100644
--- a/homeassistant/components/darksky/sensor.py
+++ b/homeassistant/components/darksky/sensor.py
@@ -15,6 +15,7 @@ from homeassistant.const import (
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
     CONF_SCAN_INTERVAL,
+    LENGTH_KILOMETERS,
     SPEED_KILOMETERS_PER_HOUR,
     SPEED_METERS_PER_SECOND,
     SPEED_MILES_PER_HOUR,
@@ -76,10 +77,10 @@ SENSOR_TYPES = {
     ],
     "nearest_storm_distance": [
         "Nearest Storm Distance",
-        "km",
+        LENGTH_KILOMETERS,
         "mi",
-        "km",
-        "km",
+        LENGTH_KILOMETERS,
+        LENGTH_KILOMETERS,
         "mi",
         "mdi:weather-lightning",
         ["currently"],
@@ -226,10 +227,10 @@ SENSOR_TYPES = {
     ],
     "visibility": [
         "Visibility",
-        "km",
+        LENGTH_KILOMETERS,
         "mi",
-        "km",
-        "km",
+        LENGTH_KILOMETERS,
+        LENGTH_KILOMETERS,
         "mi",
         "mdi:eye",
         ["currently", "hourly", "daily"],
diff --git a/homeassistant/components/demo/geo_location.py b/homeassistant/components/demo/geo_location.py
index 6fc8e9c2e89..76dea52e846 100644
--- a/homeassistant/components/demo/geo_location.py
+++ b/homeassistant/components/demo/geo_location.py
@@ -6,12 +6,12 @@ import random
 from typing import Optional
 
 from homeassistant.components.geo_location import GeolocationEvent
+from homeassistant.const import LENGTH_KILOMETERS
 from homeassistant.helpers.event import track_time_interval
 
 _LOGGER = logging.getLogger(__name__)
 
 AVG_KM_PER_DEGREE = 111.0
-DEFAULT_UNIT_OF_MEASUREMENT = "km"
 DEFAULT_UPDATE_INTERVAL = timedelta(minutes=1)
 MAX_RADIUS_IN_KM = 50
 NUMBER_OF_DEMO_DEVICES = 5
@@ -71,7 +71,7 @@ class DemoManager:
 
         event_name = random.choice(EVENT_NAMES)
         return DemoGeolocationEvent(
-            event_name, radius_in_km, latitude, longitude, DEFAULT_UNIT_OF_MEASUREMENT
+            event_name, radius_in_km, latitude, longitude, LENGTH_KILOMETERS
         )
 
     def _init_regular_updates(self):
diff --git a/homeassistant/components/geo_json_events/geo_location.py b/homeassistant/components/geo_json_events/geo_location.py
index 3435fcc50cf..2fd8466cc19 100644
--- a/homeassistant/components/geo_json_events/geo_location.py
+++ b/homeassistant/components/geo_json_events/geo_location.py
@@ -14,6 +14,7 @@ from homeassistant.const import (
     CONF_SCAN_INTERVAL,
     CONF_URL,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.core import callback
 import homeassistant.helpers.config_validation as cv
@@ -25,7 +26,6 @@ _LOGGER = logging.getLogger(__name__)
 ATTR_EXTERNAL_ID = "external_id"
 
 DEFAULT_RADIUS_IN_KM = 20.0
-DEFAULT_UNIT_OF_MEASUREMENT = "km"
 
 SCAN_INTERVAL = timedelta(minutes=5)
 
@@ -198,7 +198,7 @@ class GeoJsonLocationEvent(GeolocationEvent):
     @property
     def unit_of_measurement(self):
         """Return the unit of measurement."""
-        return DEFAULT_UNIT_OF_MEASUREMENT
+        return LENGTH_KILOMETERS
 
     @property
     def device_state_attributes(self):
diff --git a/homeassistant/components/geo_rss_events/sensor.py b/homeassistant/components/geo_rss_events/sensor.py
index 22f02a4218c..5a11136fd43 100644
--- a/homeassistant/components/geo_rss_events/sensor.py
+++ b/homeassistant/components/geo_rss_events/sensor.py
@@ -20,6 +20,7 @@ from homeassistant.const import (
     CONF_RADIUS,
     CONF_UNIT_OF_MEASUREMENT,
     CONF_URL,
+    LENGTH_KILOMETERS,
 )
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
@@ -152,7 +153,7 @@ class GeoRssServiceSensor(Entity):
             # And now compute the attributes from the filtered events.
             matrix = {}
             for entry in feed_entries:
-                matrix[entry.title] = f"{entry.distance_to_home:.0f}km"
+                matrix[entry.title] = f"{entry.distance_to_home:.0f}{LENGTH_KILOMETERS}"
             self._state_attributes = matrix
         elif status == UPDATE_OK_NO_DATA:
             _LOGGER.debug("Update successful, but no data received from %s", self._feed)
diff --git a/homeassistant/components/ign_sismologia/geo_location.py b/homeassistant/components/ign_sismologia/geo_location.py
index 21e8e1c7412..6ed3af285a3 100644
--- a/homeassistant/components/ign_sismologia/geo_location.py
+++ b/homeassistant/components/ign_sismologia/geo_location.py
@@ -14,6 +14,7 @@ from homeassistant.const import (
     CONF_RADIUS,
     CONF_SCAN_INTERVAL,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.core import callback
 import homeassistant.helpers.config_validation as cv
@@ -33,7 +34,6 @@ CONF_MINIMUM_MAGNITUDE = "minimum_magnitude"
 
 DEFAULT_MINIMUM_MAGNITUDE = 0.0
 DEFAULT_RADIUS_IN_KM = 50.0
-DEFAULT_UNIT_OF_MEASUREMENT = "km"
 
 SCAN_INTERVAL = timedelta(minutes=5)
 
@@ -235,7 +235,7 @@ class IgnSismologiaLocationEvent(GeolocationEvent):
     @property
     def unit_of_measurement(self):
         """Return the unit of measurement."""
-        return DEFAULT_UNIT_OF_MEASUREMENT
+        return LENGTH_KILOMETERS
 
     @property
     def device_state_attributes(self):
diff --git a/homeassistant/components/isy994/sensor.py b/homeassistant/components/isy994/sensor.py
index a21b484ec9b..47b9fc1d633 100644
--- a/homeassistant/components/isy994/sensor.py
+++ b/homeassistant/components/isy994/sensor.py
@@ -5,6 +5,7 @@ from typing import Callable
 from homeassistant.components.sensor import DOMAIN
 from homeassistant.const import (
     CONCENTRATION_PARTS_PER_MILLION,
+    LENGTH_KILOMETERS,
     POWER_WATT,
     SPEED_KILOMETERS_PER_HOUR,
     SPEED_METERS_PER_SECOND,
@@ -99,7 +100,7 @@ UOM_FRIENDLY_NAME = {
     "76": "Wind Direction (°)",
     "77": TIME_YEARS,
     "82": "mm",
-    "83": "km",
+    "83": LENGTH_KILOMETERS,
     "85": "ohm",
     "86": "kOhm",
     "87": "m³/m³",
diff --git a/homeassistant/components/metoffice/sensor.py b/homeassistant/components/metoffice/sensor.py
index d04f7c5f582..0682c458792 100644
--- a/homeassistant/components/metoffice/sensor.py
+++ b/homeassistant/components/metoffice/sensor.py
@@ -13,6 +13,7 @@ from homeassistant.const import (
     CONF_LONGITUDE,
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
+    LENGTH_KILOMETERS,
     SPEED_MILES_PER_HOUR,
     TEMP_CELSIUS,
     UNIT_PERCENTAGE,
@@ -70,7 +71,7 @@ SENSOR_TYPES = {
     "wind_direction": ["Wind Direction", None],
     "wind_gust": ["Wind Gust", SPEED_MILES_PER_HOUR],
     "visibility": ["Visibility", None],
-    "visibility_distance": ["Visibility Distance", "km"],
+    "visibility_distance": ["Visibility Distance", LENGTH_KILOMETERS],
     "uv": ["UV", None],
     "precipitation": ["Probability of Precipitation", UNIT_PERCENTAGE],
     "humidity": ["Humidity", UNIT_PERCENTAGE],
diff --git a/homeassistant/components/nsw_rural_fire_service_feed/geo_location.py b/homeassistant/components/nsw_rural_fire_service_feed/geo_location.py
index f0d8c901387..c8eda3690ef 100644
--- a/homeassistant/components/nsw_rural_fire_service_feed/geo_location.py
+++ b/homeassistant/components/nsw_rural_fire_service_feed/geo_location.py
@@ -16,6 +16,7 @@ from homeassistant.const import (
     CONF_SCAN_INTERVAL,
     EVENT_HOMEASSISTANT_START,
     EVENT_HOMEASSISTANT_STOP,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.core import callback
 from homeassistant.helpers import aiohttp_client, config_validation as cv
@@ -41,7 +42,6 @@ ATTR_TYPE = "type"
 CONF_CATEGORIES = "categories"
 
 DEFAULT_RADIUS_IN_KM = 20.0
-DEFAULT_UNIT_OF_MEASUREMENT = "km"
 
 SCAN_INTERVAL = timedelta(minutes=5)
 
@@ -281,7 +281,7 @@ class NswRuralFireServiceLocationEvent(GeolocationEvent):
     @property
     def unit_of_measurement(self):
         """Return the unit of measurement."""
-        return DEFAULT_UNIT_OF_MEASUREMENT
+        return LENGTH_KILOMETERS
 
     @property
     def device_state_attributes(self):
diff --git a/homeassistant/components/proximity/__init__.py b/homeassistant/components/proximity/__init__.py
index 0182f6bc072..3509b1ba8e1 100644
--- a/homeassistant/components/proximity/__init__.py
+++ b/homeassistant/components/proximity/__init__.py
@@ -3,7 +3,12 @@ import logging
 
 import voluptuous as vol
 
-from homeassistant.const import CONF_DEVICES, CONF_UNIT_OF_MEASUREMENT, CONF_ZONE
+from homeassistant.const import (
+    CONF_DEVICES,
+    CONF_UNIT_OF_MEASUREMENT,
+    CONF_ZONE,
+    LENGTH_KILOMETERS,
+)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
 from homeassistant.helpers.event import track_state_change
@@ -28,7 +33,7 @@ DEFAULT_PROXIMITY_ZONE = "home"
 DEFAULT_TOLERANCE = 1
 DOMAIN = "proximity"
 
-UNITS = ["km", "m", "mi", "ft"]
+UNITS = [LENGTH_KILOMETERS, "m", "mi", "ft"]
 
 ZONE_SCHEMA = vol.Schema(
     {
diff --git a/homeassistant/components/qld_bushfire/geo_location.py b/homeassistant/components/qld_bushfire/geo_location.py
index 8ae80ca9027..8efb1a32705 100644
--- a/homeassistant/components/qld_bushfire/geo_location.py
+++ b/homeassistant/components/qld_bushfire/geo_location.py
@@ -14,6 +14,7 @@ from homeassistant.const import (
     CONF_RADIUS,
     CONF_SCAN_INTERVAL,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.core import callback
 import homeassistant.helpers.config_validation as cv
@@ -31,7 +32,6 @@ ATTR_UPDATED_DATE = "updated_date"
 CONF_CATEGORIES = "categories"
 
 DEFAULT_RADIUS_IN_KM = 20.0
-DEFAULT_UNIT_OF_MEASUREMENT = "km"
 
 SCAN_INTERVAL = timedelta(minutes=5)
 
@@ -231,7 +231,7 @@ class QldBushfireLocationEvent(GeolocationEvent):
     @property
     def unit_of_measurement(self):
         """Return the unit of measurement."""
-        return DEFAULT_UNIT_OF_MEASUREMENT
+        return LENGTH_KILOMETERS
 
     @property
     def device_state_attributes(self):
diff --git a/homeassistant/components/usgs_earthquakes_feed/geo_location.py b/homeassistant/components/usgs_earthquakes_feed/geo_location.py
index 37934db3052..af9e82adf49 100644
--- a/homeassistant/components/usgs_earthquakes_feed/geo_location.py
+++ b/homeassistant/components/usgs_earthquakes_feed/geo_location.py
@@ -16,6 +16,7 @@ from homeassistant.const import (
     CONF_RADIUS,
     CONF_SCAN_INTERVAL,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.core import callback
 import homeassistant.helpers.config_validation as cv
@@ -38,7 +39,7 @@ CONF_MINIMUM_MAGNITUDE = "minimum_magnitude"
 
 DEFAULT_MINIMUM_MAGNITUDE = 0.0
 DEFAULT_RADIUS_IN_KM = 50.0
-DEFAULT_UNIT_OF_MEASUREMENT = "km"
+DEFAULT_UNIT_OF_MEASUREMENT = LENGTH_KILOMETERS
 
 SCAN_INTERVAL = timedelta(minutes=5)
 
diff --git a/tests/components/demo/test_geo_location.py b/tests/components/demo/test_geo_location.py
index b7b11a7b46d..5d5f2fc8106 100644
--- a/tests/components/demo/test_geo_location.py
+++ b/tests/components/demo/test_geo_location.py
@@ -4,10 +4,10 @@ from unittest.mock import patch
 
 from homeassistant.components import geo_location
 from homeassistant.components.demo.geo_location import (
-    DEFAULT_UNIT_OF_MEASUREMENT,
     DEFAULT_UPDATE_INTERVAL,
     NUMBER_OF_DEMO_DEVICES,
 )
+from homeassistant.const import LENGTH_KILOMETERS
 from homeassistant.setup import setup_component
 import homeassistant.util.dt as dt_util
 
@@ -60,10 +60,7 @@ class TestDemoPlatform(unittest.TestCase):
                     abs(state.attributes["longitude"] - self.hass.config.longitude)
                     < 1.0
                 )
-                assert (
-                    state.attributes["unit_of_measurement"]
-                    == DEFAULT_UNIT_OF_MEASUREMENT
-                )
+                assert state.attributes["unit_of_measurement"] == LENGTH_KILOMETERS
 
             # Update (replaces 1 device).
             fire_time_changed(self.hass, utcnow + DEFAULT_UPDATE_INTERVAL)
diff --git a/tests/components/gdacs/test_geo_location.py b/tests/components/gdacs/test_geo_location.py
index 255a2c50946..3b49fe2af71 100644
--- a/tests/components/gdacs/test_geo_location.py
+++ b/tests/components/gdacs/test_geo_location.py
@@ -28,6 +28,7 @@ from homeassistant.const import (
     ATTR_UNIT_OF_MEASUREMENT,
     CONF_RADIUS,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.helpers.entity_registry import async_get_registry
 from homeassistant.setup import async_setup_component
@@ -124,7 +125,7 @@ async def test_setup(hass):
             ATTR_EVENT_TYPE: "Drought",
             ATTR_SEVERITY: "Severity 1",
             ATTR_VULNERABILITY: "Vulnerability 1",
-            ATTR_UNIT_OF_MEASUREMENT: "km",
+            ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
             ATTR_SOURCE: "gdacs",
             ATTR_ICON: "mdi:water-off",
         }
@@ -140,7 +141,7 @@ async def test_setup(hass):
             ATTR_FRIENDLY_NAME: "Tropical Cyclone: Name 2",
             ATTR_DESCRIPTION: "Description 2",
             ATTR_EVENT_TYPE: "Tropical Cyclone",
-            ATTR_UNIT_OF_MEASUREMENT: "km",
+            ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
             ATTR_SOURCE: "gdacs",
             ATTR_ICON: "mdi:weather-hurricane",
         }
@@ -157,7 +158,7 @@ async def test_setup(hass):
             ATTR_DESCRIPTION: "Description 3",
             ATTR_EVENT_TYPE: "Tropical Cyclone",
             ATTR_COUNTRY: "Country 2",
-            ATTR_UNIT_OF_MEASUREMENT: "km",
+            ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
             ATTR_SOURCE: "gdacs",
             ATTR_ICON: "mdi:weather-hurricane",
         }
diff --git a/tests/components/geo_json_events/test_geo_location.py b/tests/components/geo_json_events/test_geo_location.py
index 8bfbed52a11..e10125f84ac 100644
--- a/tests/components/geo_json_events/test_geo_location.py
+++ b/tests/components/geo_json_events/test_geo_location.py
@@ -17,6 +17,7 @@ from homeassistant.const import (
     CONF_RADIUS,
     CONF_URL,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.helpers.dispatcher import DATA_DISPATCHER
 from homeassistant.setup import async_setup_component
@@ -89,7 +90,7 @@ async def test_setup(hass):
                 ATTR_LATITUDE: -31.0,
                 ATTR_LONGITUDE: 150.0,
                 ATTR_FRIENDLY_NAME: "Title 1",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "geo_json_events",
             }
             assert round(abs(float(state.state) - 15.5), 7) == 0
@@ -102,7 +103,7 @@ async def test_setup(hass):
                 ATTR_LATITUDE: -31.1,
                 ATTR_LONGITUDE: 150.1,
                 ATTR_FRIENDLY_NAME: "Title 2",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "geo_json_events",
             }
             assert round(abs(float(state.state) - 20.5), 7) == 0
@@ -115,7 +116,7 @@ async def test_setup(hass):
                 ATTR_LATITUDE: -31.2,
                 ATTR_LONGITUDE: 150.2,
                 ATTR_FRIENDLY_NAME: "Title 3",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "geo_json_events",
             }
             assert round(abs(float(state.state) - 25.5), 7) == 0
diff --git a/tests/components/geonetnz_quakes/test_geo_location.py b/tests/components/geonetnz_quakes/test_geo_location.py
index 06244227726..0264baa8e87 100644
--- a/tests/components/geonetnz_quakes/test_geo_location.py
+++ b/tests/components/geonetnz_quakes/test_geo_location.py
@@ -24,6 +24,7 @@ from homeassistant.const import (
     ATTR_UNIT_OF_MEASUREMENT,
     CONF_RADIUS,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.helpers.entity_registry import async_get_registry
 from homeassistant.setup import async_setup_component
@@ -94,7 +95,7 @@ async def test_setup(hass):
             ATTR_DEPTH: 10.5,
             ATTR_MMI: 5,
             ATTR_QUALITY: "best",
-            ATTR_UNIT_OF_MEASUREMENT: "km",
+            ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
             ATTR_SOURCE: "geonetnz_quakes",
             ATTR_ICON: "mdi:pulse",
         }
@@ -109,7 +110,7 @@ async def test_setup(hass):
             ATTR_LONGITUDE: -3.1,
             ATTR_FRIENDLY_NAME: "Title 2",
             ATTR_MAGNITUDE: 4.6,
-            ATTR_UNIT_OF_MEASUREMENT: "km",
+            ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
             ATTR_SOURCE: "geonetnz_quakes",
             ATTR_ICON: "mdi:pulse",
         }
@@ -124,7 +125,7 @@ async def test_setup(hass):
             ATTR_LONGITUDE: -3.2,
             ATTR_FRIENDLY_NAME: "Title 3",
             ATTR_LOCALITY: "Locality 3",
-            ATTR_UNIT_OF_MEASUREMENT: "km",
+            ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
             ATTR_SOURCE: "geonetnz_quakes",
             ATTR_ICON: "mdi:pulse",
         }
diff --git a/tests/components/ign_sismologia/test_geo_location.py b/tests/components/ign_sismologia/test_geo_location.py
index 0f0191f3b82..c2bd357ecc8 100644
--- a/tests/components/ign_sismologia/test_geo_location.py
+++ b/tests/components/ign_sismologia/test_geo_location.py
@@ -24,6 +24,7 @@ from homeassistant.const import (
     CONF_LONGITUDE,
     CONF_RADIUS,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
@@ -126,7 +127,7 @@ async def test_setup(hass):
                 ),
                 ATTR_IMAGE_URL: "http://image.url/map.jpg",
                 ATTR_MAGNITUDE: 5.7,
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "ign_sismologia",
                 ATTR_ICON: "mdi:pulse",
             }
@@ -142,7 +143,7 @@ async def test_setup(hass):
                 ATTR_FRIENDLY_NAME: "M 4.6",
                 ATTR_TITLE: "Title 2",
                 ATTR_MAGNITUDE: 4.6,
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "ign_sismologia",
                 ATTR_ICON: "mdi:pulse",
             }
@@ -158,7 +159,7 @@ async def test_setup(hass):
                 ATTR_FRIENDLY_NAME: "Region 3",
                 ATTR_TITLE: "Title 3",
                 ATTR_REGION: "Region 3",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "ign_sismologia",
                 ATTR_ICON: "mdi:pulse",
             }
diff --git a/tests/components/nsw_rural_fire_service_feed/test_geo_location.py b/tests/components/nsw_rural_fire_service_feed/test_geo_location.py
index 1915706ca1a..6834c557bd5 100644
--- a/tests/components/nsw_rural_fire_service_feed/test_geo_location.py
+++ b/tests/components/nsw_rural_fire_service_feed/test_geo_location.py
@@ -32,6 +32,7 @@ from homeassistant.const import (
     CONF_RADIUS,
     EVENT_HOMEASSISTANT_START,
     EVENT_HOMEASSISTANT_STOP,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
@@ -154,7 +155,7 @@ async def test_setup(hass):
                 ATTR_TYPE: "Type 1",
                 ATTR_SIZE: "Size 1",
                 ATTR_RESPONSIBLE_AGENCY: "Agency 1",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "nsw_rural_fire_service_feed",
                 ATTR_ICON: "mdi:fire",
             }
@@ -169,7 +170,7 @@ async def test_setup(hass):
                 ATTR_LONGITUDE: 150.1,
                 ATTR_FRIENDLY_NAME: "Title 2",
                 ATTR_FIRE: False,
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "nsw_rural_fire_service_feed",
                 ATTR_ICON: "mdi:alarm-light",
             }
@@ -184,7 +185,7 @@ async def test_setup(hass):
                 ATTR_LONGITUDE: 150.2,
                 ATTR_FRIENDLY_NAME: "Title 3",
                 ATTR_FIRE: True,
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "nsw_rural_fire_service_feed",
                 ATTR_ICON: "mdi:fire",
             }
diff --git a/tests/components/qld_bushfire/test_geo_location.py b/tests/components/qld_bushfire/test_geo_location.py
index ad9bdd7c536..afcd2f11802 100644
--- a/tests/components/qld_bushfire/test_geo_location.py
+++ b/tests/components/qld_bushfire/test_geo_location.py
@@ -23,6 +23,7 @@ from homeassistant.const import (
     CONF_LONGITUDE,
     CONF_RADIUS,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
@@ -122,7 +123,7 @@ async def test_setup(hass):
                     2018, 9, 22, 8, 10, tzinfo=datetime.timezone.utc
                 ),
                 ATTR_STATUS: "Status 1",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "qld_bushfire",
                 ATTR_ICON: "mdi:fire",
             }
@@ -136,7 +137,7 @@ async def test_setup(hass):
                 ATTR_LATITUDE: 38.1,
                 ATTR_LONGITUDE: -3.1,
                 ATTR_FRIENDLY_NAME: "Title 2",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "qld_bushfire",
                 ATTR_ICON: "mdi:fire",
             }
@@ -150,7 +151,7 @@ async def test_setup(hass):
                 ATTR_LATITUDE: 38.2,
                 ATTR_LONGITUDE: -3.2,
                 ATTR_FRIENDLY_NAME: "Title 3",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "qld_bushfire",
                 ATTR_ICON: "mdi:fire",
             }
diff --git a/tests/components/usgs_earthquakes_feed/test_geo_location.py b/tests/components/usgs_earthquakes_feed/test_geo_location.py
index 646878c97bd..4823d2eb2da 100644
--- a/tests/components/usgs_earthquakes_feed/test_geo_location.py
+++ b/tests/components/usgs_earthquakes_feed/test_geo_location.py
@@ -27,6 +27,7 @@ from homeassistant.const import (
     CONF_LONGITUDE,
     CONF_RADIUS,
     EVENT_HOMEASSISTANT_START,
+    LENGTH_KILOMETERS,
 )
 from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
@@ -148,7 +149,7 @@ async def test_setup(hass):
                 ATTR_TYPE: "Type 1",
                 ATTR_ALERT: "Alert 1",
                 ATTR_MAGNITUDE: 5.7,
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "usgs_earthquakes_feed",
                 ATTR_ICON: "mdi:pulse",
             }
@@ -162,7 +163,7 @@ async def test_setup(hass):
                 ATTR_LATITUDE: -31.1,
                 ATTR_LONGITUDE: 150.1,
                 ATTR_FRIENDLY_NAME: "Title 2",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "usgs_earthquakes_feed",
                 ATTR_ICON: "mdi:pulse",
             }
@@ -176,7 +177,7 @@ async def test_setup(hass):
                 ATTR_LATITUDE: -31.2,
                 ATTR_LONGITUDE: 150.2,
                 ATTR_FRIENDLY_NAME: "Title 3",
-                ATTR_UNIT_OF_MEASUREMENT: "km",
+                ATTR_UNIT_OF_MEASUREMENT: LENGTH_KILOMETERS,
                 ATTR_SOURCE: "usgs_earthquakes_feed",
                 ATTR_ICON: "mdi:pulse",
             }