Marathon County's 2026 population is estimated at 139,597, reflecting a 0.18% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Marathon County is the 10th largest county in Wisconsin. The 2010 population was 134,064 and has grown 4.13% since 2010.
Data after 2023 is projected based on recent change
Overall: 41.3 years
Female: 41.7 years
Male: 40.8 years
There are 107,273 adults, (26,553 of whom are seniors) in Marathon County.
Female: 68,553 (49.5%)
Male: 69,850 (50.5%)
The racial composition of Marathon County includes 86.98% White, 5.67% Asian, and smaller percentages for other race, Black or African American, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 120,384 | 86.98% |
| Asian | 7,850 | 5.67% |
| Two or more races | 6,769 | 4.89% |
| Other race | 2,319 | 1.68% |
| Black or African American | 800 | 0.58% |
| Native American | 251 | 0.18% |
| Native Hawaiian or Pacific Islander | 30 | 0.02% |
Marathon County 's average per capita income is $51,449. Household income levels show a median of $77,884. The poverty rate stands at 8.7%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $107,730 | $128,408 |
| Families | $98,320 | $118,904 |
| Households | $77,884 | $97,899 |
| Non Families | $44,553 | $57,552 |
Average Income
Median Household Income
Poverty Rate
