Williamson County's 2026 population is estimated at 776,641, reflecting a 3.16% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Williamson County is the 12th largest county in Texas. The 2010 population was 426,568 and has grown 82.07% since 2010.
Overall: 37.3 years
Female: 37.8 years
Male: 36.7 years
There are 510,742 adults, (86,908 of whom are seniors) in Williamson County.
Female: 337,421 (50.2%)
Male: 335,267 (49.8%)
The racial composition of Williamson County includes 59.61% White, 10.02% Asian, 6.97% Black or African American, 6.01% other race, and smaller percentages for Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 400,958 | 59.61% |
| Two or more races | 113,287 | 16.84% |
| Asian | 67,402 | 10.02% |
| Black or African American | 46,889 | 6.97% |
| Other race | 40,426 | 6.01% |
| Native American | 2,935 | 0.44% |
| Native Hawaiian or Pacific Islander | 791 | 0.12% |
Williamson County 's average per capita income is $64,836. Household income levels show a median of $111,340. The poverty rate stands at 6.43%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $151,545 | $178,517 |
| Families | $134,158 | $160,996 |
| Households | $111,340 | $140,407 |
| Non Families | $65,739 | $87,079 |
Average Income
Median Household Income
Poverty Rate