Market insights · Illinois
Mercer County, IL: growth, migration and housing
Mercer County has 15,229 residents, down 2.6% since 2020 (-0.4% in the last year). In 2022–2023, 352 households moved in and 382 moved out (-30 net), while a net $2.9M of income left. Median household income is $74,182, the median home $146,700 and median rent $786 a month.
In Illinois: 67th of 102 counties for 5-year population growth · 59th of 102 counties for net in-migration (per resident) · 27th of 102 counties for median household income · 41st of 102 counties for median home value.
Where new residents came from
Top counties by households (tax returns) moving to Mercer County, 2022–2023 (IRS).
| From | Households (tax returns) | Their income (AGI) |
|---|---|---|
| Rock Island County, IL | 125 | $6.9M |
| Scott County, IA | 38 | $2.1M |
| Henry County, IL | 27 | $1.5M |
| Knox County, IL | 20 | $1.2M |
Where leavers went
Top counties by households leaving Mercer County, 2022–2023 (IRS).
| To | Households (tax returns) | Their income (AGI) |
|---|---|---|
| Rock Island County, IL | 108 | $6.8M |
| Scott County, IA | 40 | $2.1M |
| Knox County, IL | 29 | $1.2M |
| Warren County, IL | 26 | $1.1M |
| Henry County, IL | 25 | $1.4M |
BizyFi in Mercer County
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Sources: U.S. Census Bureau population estimates (vintage 2025), American Community Survey 5-year (2024), and IRS Statistics of Income county-to-county migration data (2022–2023). Migration counts are tax returns (roughly households) moving between U.S. counties; the IRS suppresses very small flows. Growth rates, per-1,000 figures, rent share and state ranks are BizyFi calculations. Data updated 2026-10-17. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.