On March 3, 1879, the post office was moved from the west bank of the Missouri River to the railroad's city site within blocks of Mandan's first railroad depot and freight building at Main Street and Stark Avenue (today's Collins Avenue). Four city names coincided exactly with four postmasters. The original railroad work camp's post office in 1878 was known as Morton. The name Mandan stuck for only eight days in March 1879 before being renamed Cushman by a postmaster with that surname. In September 1879, the post office returned to its designation of Mandan.