Green’s Dictionary of Slang

1. a shanty town.

1875

M. Thompson Hoosier Mosaics 52: His general appearance was that of a well dressed gentleman, which of itself was enough to excite remark in Jimtown.

2. Miami, FL.

1907

Pensacola Jrnl (FL) 15 Aug. 4/1: Everybody who intends visiting the big show at ‘Jimtown’ should make a point to be there on Florida day.

3. the poor (thus often black or Hispanic) part of a town.

1946		McWilliams Southern Calif. Country 218: The typical citrus worker settlement is the mexican town or, in the parlance of the region, the ‘jim-town’ [DARE].
1967–9		in DARE.