A total of around 1,000 acres were listed for sale in Northumberland County recently, representing a combined $24 million in Northumberland County farms and rural land for sale. Northumberland County ranks 48th out of 67 counties in the Independence State for the combined amount of land currently advertised for sale. Of all locations in Northumberland County with farms, rural land, hunting land and other land for sale, Northumberland featured the most land for sale. Northumberland County is the 48th largest county (477 square miles) in Pennsylvania. It's located in the Alleghenies & Valleys Pennsylvania region of Pennsylvania.