Of 10 counties in the state, Sullivan County ranks eighth by size (552 square miles). Sullivan County is in Central New Hampshire. New Hampshire's Sullivan County has almost 1,000 acres of riverfront 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 nearly $500,000. Browse all waterfront property for sale in Sullivan 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! The most common type of land for sale by combined acreage in Sullivan County is residential property.