| Official Name: | Dewmaine, Illinois |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | Illinois#USA |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Williamson |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 430 |
| Postal Code Type: | ZIP Code |
| Postal Code: | 62918 |
| Area Code: | 618 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 407173 |
Dewmaine was an unincorporated African-American coal-mining community in Williamson County, Illinois. Today the area is almost completely non-residential and vacant land, though it now sits at the northern edge of Carterville. Its name is an amalgamation of Admiral Dewey and the USS Maine from the Spanish–American War.[1]
A post office was established at Dewmaine in 1901, and remained in operation until 1931.[2] It is now served by the Carterville post office. Estimated population in 1958 was 50.[3]