Thornton population
Thornton, Colorado had an estimated 147,766 residents on July 1, 2025, the 195th-largest city in the US. That is up 24.4% since the 2010 Census and up 79.1% since 2000.
- Population, July 2025
- 147,766+4.2% since April 2020
- People per sq mile
- 4,04636.5 sq mi of land
- Median age
- 34.710.8% are 65 or older
- Households with kids
- 36.6%with anyone under 18
Population by year, 2000 to 2025
| Year | Population | Change | Basis |
|---|---|---|---|
| 2025 | 147,766 | -604 | Estimate, July 1 |
| 2024 | 148,370 | +2,437 | Estimate, July 1 |
| 2023 | 145,933 | +2,575 | Estimate, July 1 |
| 2022 | 143,358 | +531 | Estimate, July 1 |
| 2021 | 142,827 | +958 | Estimate, July 1 |
| 2020 | 141,869 | -5,060 | April 2020 estimates base |
| 2019 | 146,929 | +1,770 | Estimate, July 1 |
| 2018 | 145,159 | +2,975 | Estimate, July 1 |
| 2017 | 142,184 | +3,759 | Estimate, July 1 |
| 2016 | 138,425 | +3,234 | Estimate, July 1 |
| 2015 | 135,191 | +3,246 | Estimate, July 1 |
| 2014 | 131,945 | +3,279 | Estimate, July 1 |
| 2013 | 128,666 | +3,240 | Estimate, July 1 |
| 2012 | 125,426 | +3,019 | Estimate, July 1 |
| 2011 | 122,407 | +3,635 | Estimate, July 1 |
| 2010 | 118,772 | +2,426 | 2010 Census (April 1) |
| 2009 | 116,346 | +4,013 | Estimate, July 1 |
| 2008 | 112,333 | +3,580 | Estimate, July 1 |
| 2007 | 108,753 | +3,579 | Estimate, July 1 |
| 2006 | 105,174 | +4,160 | Estimate, July 1 |
| 2005 | 101,014 | +3,872 | Estimate, July 1 |
| 2004 | 97,142 | +3,120 | Estimate, July 1 |
| 2003 | 94,022 | +2,970 | Estimate, July 1 |
| 2002 | 91,052 | +4,001 | Estimate, July 1 |
| 2001 | 87,051 | +4,545 | Estimate, July 1 |
| 2000 | 82,506 | April 2000 estimates base |
Year-to-year changes across 2010 and 2020 mix census counts with estimates, so small jumps at those years are partly method changes.
Frequently asked questions
What is the population of Thornton in 2025?
The Census Bureau estimates Thornton had 147,766 residents on July 1, 2025, making it the 195th-largest city in the US.
Is Thornton growing?
Yes. Thornton has grown 24.4% since the 2010 Census (118,772 people), and grown 4.2% since 2020.
What was the population of Thornton in 2000?
About 82,506 (the Census Bureau's April 2000 estimates base). By the 2010 Census it was 118,772.
How dense is Thornton?
Thornton has about 4,046 people per square mile of land (36.5 square miles).
More about Thornton
See cost of living, jobs and commutes in Thornton, Thornton weather by month, or every Thornton ZIP code. For the biggest cities in the country, see the largest US cities.