The Larchmont Post Office was established as a fourth class office Jan. 11, 1891, in a Pierce County, Wash., real estate development known as Larchmont, named after Larchmont, N.Y., likely the former home of the postmaster or developer. The locale was in the vicinity of South 96th St., and Pacific Ave., and the post office operated until Jan. 31, 1905, when it was closed and mail service operated out of Tacoma.
From the description of United States Post Office, Larchmont, Wash., records, 1893 Mar.-1904 Dec. (Washington State Historical Society). WorldCat record id: 696012101