On June 24, 1874, the D'wamish Post Office opens. Henry H. Miller is the first postmaster. The post office is located on the west side of the Duwamish River within the future city limits of Seattle at about 1st Avenue S and Michigan Street (1998 street names). The post office did not operate from October 18, 1889 to August 30, 1890.
The name of the D'wamish Post Office changed to Georgetown on June 19, 1901. George R. Street was appointed postmaster.
On August 31, 1910, Georgetown became a branch of the Seattle Post Office after the area was annexed to the city of Seattle. Georgetown is located five miles south of the business district of Seattle.