The total value of land for sale in Union County, Pennsylvania, recently on Land.com was approximately $12 million. This represents approximately 1,000 acres of farms, hunting land and other rural land and acreage for sale in Union County. Union County ranks 61st in the state for the total acreage of land currently advertised for sale. Lewisburg had the most land for sale. From an economic perspective, government and state-level services contribute most to Union County's overall GDP. Union County is the 64th largest county (317 square miles) in Pennsylvania. It's located in the Alleghenies & Valleys Pennsylvania region of the state.