Middleburg is a borough in Snyder County, located in Central Pennsylvania's Susquehanna River Valley. The population was 1,309 at the 2010 census. It is the county seat of Snyder County. Middleburg is part of the Selinsgrove, PA Micropolitan Statistical Area, and is also part of the larger Bloomsburg-Berwick-Sunbury, PA Combined Statistical Area.
Native Americans had lived in the region for centuries. White settlers are recorded living in the area in 1755. Middleburg was originally named Swinefordstown (Swinefordstettle in the Pennsylvania Dutch dialect) after John Albright Swineford who ran a tavern here in 1787. He was also the owner of land located on the north bank of the Middle Creek on which engineer Frederick Evans laid out the town in 1800. This town became known as Middleburgh circa 1825, and was incorporated as a borough in 1864.
A portion of the site that Middleburg occupies was the location of the Stump's Run Massacre in January 1768. Stump's Run is located to the west of the Glendale Cemetery and is also near the Snyder County Historical Society. In this incident, two colonists named Frederick Stump and John Ironcutter were found to be responsible for the deaths of four Native American men, three Native American women, and three children over a two-day period.