Snyder County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 39,736. The county seat is Middleburg. Snyder County was formed in 1855 from parts of Union County. The county is part of the Central Pennsylvania region of the state. Snyder County comprises the Selinsgrove, PA Micropolitan Statistical Area, which is also included in the Bloomsburg-Berwick-Sunbury, PA Combined Statistical Area.