Cowlitz County's 2026 population is estimated at 115,866, reflecting a 0.82% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Cowlitz County is the 12th largest county in Washington. The 2010 population was 102,358 and has grown 13.2% since 2010.
Data after 2023 is projected based on recent change
Overall: 41.5 years
Female: 42.5 years
Male: 40.5 years
There are 87,129 adults, (22,230 of whom are seniors) in Cowlitz County.
Female: 56,283 (50.1%)
Male: 56,077 (49.9%)
The racial composition of Cowlitz County includes 83.17% White, and smaller percentages for other race, Native American, Asian, Black or African American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 93,447 | 83.17% |
| Two or more races | 11,560 | 10.29% |
| Other race | 3,330 | 2.96% |
| Native American | 1,452 | 1.29% |
| Asian | 1,351 | 1.2% |
| Black or African American | 759 | 0.68% |
| Native Hawaiian or Pacific Islander | 461 | 0.41% |
Cowlitz County 's average per capita income is $51,452. Household income levels show a median of $76,531. The poverty rate stands at 12.2%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $105,071 | - |
| Families | $90,861 | $110,788 |
| Households | $76,531 | $95,669 |
| Non Families | $44,970 | $60,191 |
Average Income
Median Household Income
Poverty Rate