Mercer is a borough in Mercer County, Pennsylvania, United States. The population was 2,002 at the 2010 census. It is the county seat of Mercer County. Mercer is part of the Youngstown-Warren-Boardman, OH-PA Metropolitan Statistical Area. The community was named after physician Brigadier General Hugh Mercer. Brigadier General Mercer was a close friend to General Washington and became a rallying point for the Battle of Princeton. The town is also known... Show more

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