In September 1915, North Dakota Governor Louis Benjamin Hanna, a successful Red River Valley businessman with interests in lumber, grain, and banking, acquired the Inter-Ocean Hotel and renamed it the Lewis and Clark Hotel. The original structure was demolished in 1917 and replaced by a new hotel costing $200,000 (about $5,026,000 in 2025 dollars).
The four-story pressed-brick building measured 150 by 130 feet and featured white enameled ornamental trimmings. Hanna initially leased it to Keller & Boyd, which also operated Fargo's Waldorf Hotel. Newspapers called the structure "The Pride of Mandan" and "architecturally one of the most beautiful hotels in the Northwest." It was listed in the National Register of Historic Places in 1983.
The building was designed by architect William J. Gage. He was born in New York City, studied at the University of Illinois. He worked for Long, Lamoreaux and Long of Minneapolis in 1911 and Ellerbe and Round of St. Paul from 1912 to 1913. After moving to Fargo in 1913, he drafted for Haxby and Gillespie before forming a partnership with Archie Ashelman in 1915. Gage moved to Seattle around 1919 and California in 1921. His surviving work also includes the City Hall in Beverly Hills, CA.
A January 1930 fire damaged the rear of the hotel. Fargo architect W. E. Kurke coordinated a 1935 repair and three-story expansion that added 10 apartments and 10 hotel rooms. The project cost $18,000 (about $423,000 in 2025 dollars).
Early tenants included Merchants National Bank. Business offices later occupied the ground floor, and a community church moved into the former billiards room.
In July 1985, Ben and Dan Hanna sold the building to Lewis and Clark Investments, Inc. Its major stockholders included William Clairmont of Bismarck, Wallace Joersz, and Dan Hanna of Mandan. Using a $975,000 MIDA bond package, the company converted 67 hotel rooms into 45 rent-subsidized one- and two-bedroom apartments. The lobby was later remodeled, and rear meeting rooms with skylights reopened for public use.