Union County is in Alleghenies & Valleys Pennsylvania. Of the 67 counties in the Independence State, 317-square-mile Union County ranks 64th by size. Pennsylvania's Union County includes roughly 1,000 acres of residential land and property for sale based on recent Land Network data. The combined market value of farms, hunting land and other rural land and acreage for sale here was around $18 million. The average price of residential land for sale in Union County was $586,909. Browse all residential land and rural property for sale in Pennsylvania to find residential land and properties that suit your lifestyle needs, from existing residential homes and estates to land ready for future residential-property development.