Mercer County is in Central North Dakota. Of the 53 counties in the Rough Rider State, Mercer County ranks 35th in terms of size (711,994 acres). Browse all waterfront property for sale in Mercer 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 Mercer County is residential property.