Of three counties in the First State, New Castle County is third in terms of its size (494 square miles). New Castle County is in the Northern Delaware region. Recent listings of farms for sale in New Castle County, Delaware, totals almost 1,000 acres and a combined market value of around $3 million. The most common type of land for sale by combined acreage in New Castle County is house. The average price of farms for sale in New Castle County was $1 million. Browse all Delaware farms for sale on the Land Network to find the farm, cattle operation, hobby farm or other farm property that's right for your future business or individual needs.