Hill County Montana (Historic Districts) has 3 places on the National Register of Historic Places including 2 places of National significance and 2 places of Statewide significance. Significant places include Fort Assinniboine, Fort Assinniboine (Boundary Increase), Fort Assinniboine and Fort Assinniboine (Boundary Increase) and Fort Assinniboine.
Some of the country's most noteable architects helped create the Hill County places including Col. J.G.C. Lee, L.K. Devlin, Colonel J.G.C. Lee and Colonel C.A. Broadwater. Prominent architectural styles found in Hill Country are Bungalow/Craftsman, Colonial Revival and Gothic Revival.