The town was named after the Revolutionary War hero Hugh Mercer. Landmarks include Ingalls House, Mercer Union Meetinghouse and Henry Knox Thatcher House. Mercer is the birthplace of Frank Munsey, publisher and politician.
- CountySomerset County
- Population709 (2020 U.S. Census)
- Historic places3 on the National Register






















Ingalls House
Mercer Union Meetinghouse