THE MONROE COUNTY LAND BRIEF
Land in the
Southern Illinoian Till Plain setting.
Monroe County has 385.3 square miles of land in Illinois. 3 mapped landscape regions meet across Monroe County: Southern Illinoian Till Plain, Karstic Northern Ozarkian River Bluffs, Middle Mississippi Alluvial Plain.
Broad terraced river valleys contrast with wooded slopes and dissected glacial plains. Bottomland settings and upland oak landscapes occur close together across the Interior River Valleys and Hills.
Regional context: Interior River Valleys and Hills ↗ · Regional mapping across the county footprint
Where the landscape changes
Monroe County intersects 3 mapped regional units. The largest mapped shares are:
- Southern Illinoian Till Plain36.5%
- Karstic Northern Ozarkian River Bluffs32.6%
- Middle Mississippi Alluvial Plain31%
Finding your parcel within Monroe County
The atlas lists 7 cities, towns, townships, and Census communities associated with Monroe County, including Columbia, Waterloo, Dupo. The list includes overlapping geography types and does not divide the county into exclusive service areas.
Monroe County by land and water
The Census records 13 square miles of water within Monroe County, or 3.3% of its total area. That share is close to Monroe County’s 3.3%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, Monroe County has 1,306.1 times the land area of nearby Maeystown village (0.3 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Randolph County, St. Clair County within Illinois. A tract near one of these lines should be matched to the county identifier on its own records.

