The main building was inaugurated in 1926, following the county decision to build a new hospital at Sandnessjøen in 1916. The architect Lars Solberg from Trondheim was appointed in 1917 to carry out the work. The architect Gunnar Stabell took over, following Solberg's death in 1921. Solberg and Stabell were designing the hospital at Bodø at the same time and their work resembled each other's.

The entrance sections on the northern side are painstakingly finished with bevelled råkopp around the door openings and some of the original doors have been preserved.