S River Street is just ½ a mile long, and none of it parallels the Duwamish River. The reason behind this is the same reason S Front Street is perpendicular to the waterway — the rechanneling of the Duwamish River that began in 1913. In Joseph R. McLaughlin’s Water Front Addition to the City of Seattle, filed in 1906, Front Street had a horseshoe shape. North Front Street is today’s Front Street, and South Front Street was changed to River Street in 1907, when West Seattle was annexed to Seattle. The Baist Atlas depiction of the Oxbow, below left, is from 1912, so has the modern name.
Today’s S River Street begins at 7th Avenue S and goes ½ a mile west, ending at 1st Avenue S, below the 1st Avenue S Bridge.