Of three counties in the state, 494-square-mile New Castle County ranks third by size. New Castle County is in the Northern Delaware region. The most common type of land for sale by combined acreage in New Castle County is house. Browse all waterfront property for sale in New Castle County on the Land Network to find the marina, lakefront and other recreational property that meets your needs, from waterside land perfect as a retirement investment to existing residential waterfront land and property for hunting, fishing and other outdoor-recreation pursuits!