Williamstown traces its roots back to 1820, when it was founded by (and named for) Capt. William Arnold on land awarded to him for his service in the Revolutionary War. Its motto of "Come Grow With Us" on the City Crest is an invitation to businesses and families to establish roots.

The county seat of Grant County is conveniently located off of I-75 about halfway between Cincinnati and Lexington, and much of the town's "country feel" centers around Lake Williamstown, a 330-acre water reservoir and recreational lake whose marina is open to the public April-September. The city is known for its community festivals — from Winter Wonderland to Derby Day — as well as the Grant County Fair.

Williamstown is home to local branch operations of Northern Kentucky University and St. Elizabeth Healthcare.