This townsite was founded in the early 1880's by the Great Northern Railroad as a rival to the Northern Pacific Railroad townsite of Mayville two miles to the east. It is located in Sections 35 & 36-147-53, Viking Township and Section 2-146-53, Roseville Township. The post office was established January 19, 1882 with Dr. James D. McKenzie as Postmaster, and the following year the town incorporated as a village. In 1885 the first insurance company in Dakota Territory was chartered here. The elevation is 970, the Zip Code is 58274, and a peak population of 641 was recorded in 1950. The name is said to note the fact that railroad officials thought it was midway between Portland, Maine and Portland, Oregon, both of which were named for Portland, Dorsetshire, England.