Williamstown is an unincorporated community in southern Madison Township, Hancock County, Ohio, United States.

Williamstown was laid out in 1834 by John W. Williams, and named for him.

[3] A post office called Eagle was established in 1834, and the name was changed to Williamstown in 1868.

[4] The post office service was suspended in 2007 and it was discontinued in 2009.

This Hancock County, Ohio state location article is a stub.