Monroe County, Illinois Cities (2024)

Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)

City
Rank
2024 Pop.
2020 Pop.
Change
Density (/mi²)
Area (mi²)
Type
Waterloo111,19011,0050.41%1,3598.2City
Columbia210,89911,033-0.31%1,03310.6City
Valmeyer31,2061,228-0.5%3523.4Village
Prairie Rocher45125000.59%8970.6Village
Hecker5414428-0.96%1,5510.3Village
Ruma6309312-0.32%4160.7Village
Maeystown7147149-0.68%4980.3Village
Floraville826308.33%3290.1CDP
Fults92426-4%4530.1Village

Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.

What is the largest city in Monroe County, Illinois?

Waterloo is the largest city in Monroe County.

What is the smallest city in Monroe County, Illinois?

Fults is the smallest city in Monroe County.

How many cities are in Monroe County?

There are 9 cities in Monroe County, Illinois.

Frequently Asked Questions