4th most populous of 64
With 578,533 residents in 2024, Jefferson County ranks 4th by population among Colorado's 64 counties and is home to 9.7% of the state's residents.

Jefferson County has the 4th highest median household income in Colorado ($110,656) and the 4th largest economy ($46.2 billion GDP).
Jefferson County is home to 578,533 people (2024 estimate) on 764 square miles of land. This page brings together official U.S. Census Bureau population estimates since 2000, the components of change—births, deaths and migration—American Community Survey indicators on income, housing, poverty and education, BEA economic accounts and BLS unemployment.
Pick an indicator to see its long-run evolution.
U.S. Census Bureau: intercensal estimates 2000–2009, Vintage 2020 (2010–2019) and Vintage 2024 (2020–2024), July 1.
| Indicator | Value | Year and source |
|---|---|---|
| Population estimate | 578,533 | 2024 · U.S. Census Bureau |
| Population, 2010 Census | 534,543 | 2010 · U.S. Census Bureau |
| Population, 2000 | 526,251 | July 1, 2000 · Census intercensal |
| Change since 2000 | +9.9% | 2000–2024 · Census |
| International migration | +1,911 | 2024 · Census Vintage 2024 |
| Domestic migration | −1,476 | 2024 · Census Vintage 2024 |
| Birth rate | 9.5 per 1,000 | 2024 · calculated |
| Death rate | 8.8 per 1,000 | 2024 · calculated |
| Population rank in Colorado | 4th of 64 | 2024 · calculated |
| Per capita personal income | $88,698 | BEA, 2024 · official |
| Gross domestic product | $46.2 billion | BEA, current dollars, 2024 · official |
| Median household income | $110,656 | ACS 2020–2024 5-year · official |
| Poverty rate | 6.7% | ACS 2020–2024 5-year · official |
| Bachelor’s degree or higher | 52.0% | Age 25+, ACS 2020–2024 5-year · official |
| Foreign-born residents | 6.3% | ACS 2020–2024 5-year · official |
| Median home value | $637,600 | ACS 2020–2024 5-year · official |
| Median gross rent | $1,861/month | ACS 2020–2024 5-year · official |
| Median age | 40.5 years | ACS 2020–2024 5-year · official |
| Households | 241,735 | ACS 2020–2024 5-year · official |
| Owner-occupied homes | 70.7% | ACS 2020–2024 5-year · official |
Comparable indicators for Jefferson County, Colorado and the United States.
| Indicator | County | Colorado | U.S. | Reference |
|---|---|---|---|---|
| Population change 2020–2024 | −0.8% | +3.2% | +2.6% | Census Vintage 2024 |
| Birth rate (per 1,000) | 9.5 | 10.5 | 10.6 | 2024 |
| Death rate (per 1,000) | 8.8 | 7.6 | 9.1 | 2024 |
| Net migration rate (per 1,000) | 0.8 | 6.5 | 8.2 | 2024 |
| Population density (/mi²) | 756.9 | 57.5 | 96.3 | 2024 |
| Per capita personal income | $88,698 | $83,055 | $73,204 | BEA, 2024 |
| Median household income | $110,656 | $95,470 | $80,734 | ACS 2020–2024 5-year |
| Poverty rate | 6.7% | 9.4% | 12.5% | ACS 2020–2024 5-year |
| Bachelor’s degree or higher | 52.0% | 45.7% | 35.7% | Age 25+, ACS 2020–2024 5-year |
| Foreign-born residents | 6.3% | 9.8% | 14.1% | ACS 2020–2024 5-year |
| Median home value | $637,600 | $539,400 | $332,700 | ACS 2020–2024 5-year |
| Median gross rent | $1,861/month | $1,761/month | $1,413/month | ACS 2020–2024 5-year |
| Median age | 40.5 years | 37.7 years | 38.9 years | ACS 2020–2024 5-year |
| Owner-occupied homes | 70.7% | 66.2% | 65.2% | ACS 2020–2024 5-year |
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With 578,533 residents in 2024, Jefferson County ranks 4th by population among Colorado's 64 counties and is home to 9.7% of the state's residents.
Its population went from 526,251 in 2000 to 578,533 in 2024, a change of +9.9%, compared with +37.7% for Colorado as a whole.
In the year to July 2024 the county recorded 5,471 births and 5,078 deaths, so births outnumbered deaths by 393.
Annual Census estimates since 2000 put the county's highest population at 583,169 in 2020. The 2024 figure is 4,636 lower.
Jefferson County has about 756.9 residents per square mile of land, ranking 4th of 64 counties; Colorado averages 57.5.
With a median household income of $110,656 (ACS 2020–2024 5-year), the county ranks 4th of 64 Colorado counties; the state median is $95,470.
Its economy produced $46.2 billion of GDP in 2024 (BEA), 4th largest among 64 Colorado counties.
Real GDP grew 1.3% in 2024, adjusted for inflation (BEA, chained 2017 dollars).