There were many locations for the post office in Columbia. This is a list of most of those locations.
Stamps issued 1851
1852 D. O. and James Mills buy a lot which has a frame building which houses the post office in the back.
1853 The bank, post office and Hunnewell's book and stationery store are in the building.
1861 March - W. O. Sleeper buys the hotel and sells it to Westley, Wilder and Wheeler who remodel the building and change the name to "The Post Office Building" and open a bookstore and stationery in addition to the post office.
1867 A Mr. Bacon becomes postmaster, in addition to the post office they have groceries, dishes, miners' and farmers' implements and hardware.
Their building was in the middle of the intersection of Washington and Main Streets before Washington street was moved north.
1871 April 25 - P. B. Bacon insures a frame store with Duchow. As his residence was on Green Street and the 1871 map shows Bacon as the owner of this lot he must have purchased it before this date. He also ran the post office while located in this building.
1873 Edward Elias has the post office until 1877.
1881 Tibbits becomes the postmaster, so the post office returns to the bank building until 1895.
1893 March - Matthew Brady, Sr. leases the building for a grocery store and post office. After his death, his sons continue the store and post office until 1899.
1899 Post office returns until 1911.
1927 The post office is on the lower floor.
1960 Postmaster is Mable (Ponce) Draper.
1963 Post office moves to Jackson street to Solari Building.
1968-1970s Warren Schultz was the Postmaster.
1972 31 May - U.S. Post Office given a ten year contract. (Park & Concessionaire report 1974-75)
1998 March 30 - Post Office left.