Colorado · Census place 0877290
Thornton, Colorado
Thornton is a city in Adams County, Colorado with an estimated 146,689 residents on July 1, 2024. It is the 6th largest of 149 incorporated places of 1,000+ people in the state.
- Population 2024
- 146,689
- #6 of 149 in Colorado
- Change since 2020
- +3.2%
- +4,498 people
- Land area
- 36.5 sq mi
- + 2.01 sq mi water
- Density
- 4,017 / sq mi
- State median 1,848
Measure from here
Tools and pages that start from Thornton
Thornton population, 2020 to 2024
Thornton added 4,498 residents from July 2020 to July 2024, a change of +3.2%. In the latest year it moved by +1,156. Among 79 Colorado places of 5,000 or more, that growth ranks 38th; the median place changed by +3.0%. The median place of 5,000+ in Colorado has 14,061 people, so Thornton is 10.4 times that size.
Thornton covers 36.52 square miles of land and 2.01 of water, for 4,017 people per square mile of land. The median Colorado place of 5,000+ has 1,848, so Thornton is denser than the typical town.
What county Thornton is in
All of Thornton's residents live in Adams County, which had 542,973 residents in 2024. Thornton holds 27.0% of the county's population. The shaded shape is on the map above; dots mark the eight nearest places.
ZIP codes in Thornton
6 ZIP Code Tabulation Areas (ZCTAs) overlap Thornton by at least 10% of the ZCTA's or the city's land: 80023, 80229, 80233, 80241, 80260, 80602. ZCTAs are Census approximations of USPS ZIP code delivery areas. The list comes from the 2020 ZCTA to place relationship file, so a city that annexed land after 2020 may reach into ZIP codes not listed here.
Where Thornton is
The Census internal point of Thornton is at 39.920400, -104.941400. Denver, the capital, is 12.7 miles S in a straight line. The nearest larger place is Denver, CO (729,019 people), 11.4 miles away. The nearest city of 100,000 or more is Westminster, CO, 7.0 miles away. The ground at the internal point is about 1,584 m (5,197 ft) above sea level.
Internal point
- Decimal
- 39.920400, -104.941400
- DMS
- 39°55'13.44"N 104°56'29.04"W
- UTM
- 13N 505007.9E 4418924.1N
- Geohash
- 9xj7h5210
- Plus code
- 85FQW3C5+5C
- Time zone
- America/Denver
Daylight in Thornton
At 39.92° N, Thornton gets about 15 h 00 min of daylight around the June solstice and 9 h 20 min around the December solstice, a swing of 5 h 40 min. Figures are sunrise to sunset from the SunCalc model for June 21 and December 21, 2026. Month-by-month sunrise and sunset times are on the Thornton daylight page.
Places near Thornton
The eight nearest incorporated places of 1,000+ in Colorado, measured between internal points. The closest is Northglenn, 2.2 miles away, with 38,287 people.
Questions people ask
What is the population of Thornton, CO?
146,689 on July 1, 2024, in the Census Vintage 2024 estimates. That is up 4,498 (3.2%) from 142,191 in July 2020.
What county is Thornton in?
Adams County. All of its residents live in that county.
What ZIP codes cover Thornton?
6 ZIP Code Tabulation Areas overlap it by at least 10% of either area: 80023, 80229, 80233, 80241, 80260, 80602.
How far is Thornton from Denver?
12.7 miles (20.5 km) in a straight line, heading S from Thornton.
What is the nearest larger city to Thornton?
Denver, CO, with 729,019 residents, 11.4 miles away between internal points.
Sources and data as of
Data as of: Census Vintage 2024 subcounty estimates (July 1, 2024), 2024 Gazetteer places, 2020 ZCTA to place relationship file.
- 01Census Vintage 2024 subcounty population estimates
- 02Census 2024 Gazetteer, places
- 03Census 2020 ZCTA to place relationship file
- 04Census 2024 cartographic boundary file, counties (1:5,000,000)
- 05Open-Meteo forecast API (time zone and Copernicus GLO-90 elevation) (last verified 2026-09-30)
How every number is computed: methodology. Spotted a wrong figure? Report an error.