Merrimac, Illinois is a small unincorporated community in the historic Moredock Precinct of Monroe County, Illinois, United States. It is located in the American Bottoms, adjacent to the Mississippi River levee due south of that river's confluence with the Meramec. It takes its name from this river whose name was translated as 'Ugly Water' from Algonquian by French Jesuits in the area. However scholars of the language translate it as 'place of strong current', which would certainly seem consistent.

Merrimac, Illinois
Etymology: Meramec River
Merrimac is located in Illinois
Merrimac
Merrimac
Merrimac is located in the United States
Merrimac
Merrimac
Coordinates: 38°22′15″N 90°20′00″W / 38.37083°N 90.33333°W / 38.37083; -90.33333
CountryUnited States
StateIllinois
CountyMonroe
Precinct15
Elevation
404 ft (123 m)
Time zoneUTC-6 (CST)
 • Summer (DST)UTC-5 (CDT)
Postal code
62295
Area code618