The total value of farmsand rural real estate for sale in Union County, Pennsylvania, recently on Land.com was nearly $10 million. This represents 1,000 acres of land and rural real estate for sale in Union County. Union County ranks 60th in the Keystone State for the total acreage of land currently advertised for sale. Of all farms, rural land, hunting land and other land for sale in Union County, 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 Pennsylvania's 64th biggest county (317 square miles). It's located in the Alleghenies & Valleys Pennsylvania region of Pennsylvania.