Market insights · Illinois
Monroe County, IL: growth, migration and housing
Monroe County has 34,840 residents, down 0.3% since 2020 (-0.8% in the last year). In 2022–2023, 737 households moved in and 769 moved out (-32 net), bringing in a net $3.2M of income. Median household income is $102,880, the median home $282,100 and median rent $1,042 a month.
In Illinois: 21st of 102 counties for 5-year population growth · 37th of 102 counties for net in-migration (per resident) · 7th of 102 counties for median household income · 8th of 102 counties for median home value.
Where new residents came from
Top counties by households (tax returns) moving to Monroe County, 2022–2023 (IRS).
| From | Households (tax returns) | Their income (AGI) |
|---|---|---|
| St. Clair County, IL | 218 | $14.4M |
| St. Louis County, MO | 124 | $10.4M |
| Randolph County, IL | 60 | $4.4M |
| St. Louis city, MO | 38 | $2.8M |
| Jefferson County, MO | 37 | $2.8M |
| Madison County, IL | 34 | $2.6M |
Where leavers went
Top counties by households leaving Monroe County, 2022–2023 (IRS).
| To | Households (tax returns) | Their income (AGI) |
|---|---|---|
| St. Clair County, IL | 168 | $9.7M |
| St. Louis County, MO | 118 | $8.1M |
| Randolph County, IL | 52 | $2.7M |
| St. Louis city, MO | 39 | $2.8M |
| Jefferson County, MO | 36 | $2.1M |
| Madison County, IL | 34 | $1.7M |
BizyFi in Monroe 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.