Postbellum
After the war, Williams served as a military administrator in southern Arkansas until he left the service on January 15, 1866. He returned to Michigan, but faced financial difficulties that forced him to take a post as the U.S. Minister at San Salvador, a position in which he served until 1869. He ran for governor of Michigan in 1870, but was not elected.
Williams was elected as a Democrat to the 45th United States Congress from Michigan's 1st congressional district, serving from March 4, 1875, to December 21, 1878. For part of his time in congress he served as chairman of the Committee on the District of Columbia.
Williams suffered a stroke on December 21, 1878, and died in the U.S. Capitol Building, and is buried in Elmwood Cemetery in Detroit.
Read more about this topic: Alpheus S. Williams