In the United States, a
river mile is a measure of distance in
miles along a
river from its
mouth. River mile numbers begin at zero and increase further upstream. The corresponding metric unit using
kilometers is the
river kilometer. They are analogous to vehicle roadway
mile markers, except that river miles are rarely marked on the physical river; instead they are marked on navigation charts, and topographic maps. Riverfront properties are sometimes partially legally described by their river mile.