Complex sentence: The Office of Historic Preservation currently lists 62 historic properties in Herlong on its Historic Properties Data File for Lassen County, one of the last counties in the American west that is still considered "open range" land.
Split into simpler sentences: The Office of Historic Preservation currently lists 62 historic properties in Herlong on its Historic Properties Data File for Lassen County. Herlong is in Lassen County, which is one of the last counties in the American west that is still considered "open range" land.