Montana - Area of significance: Architecture
| 4K Ranch |
| Acme Building |
| Adams Block |
| Adams Hotel |
| Adam's, J. C., Stone Barn |
| Administration Building |
| Ainsworth House |
| Airway Radio Station |
| Alberton School |
| Alexander and Busey Houses |
| Algeria Shrine Temple |
| Allison-Reinkeh House |
| Alpine Apartments |
| Anaconda Commercial Historic District |
| Anaconda Saddle Club |
| Ancient Order of Hibernians Hall |
| Anderson, Herman and Hannah, House |
| Anderson House |
| Anderson School |
| Anderson Style Shop |
| Andrus Hotel |
| Ant Flat Ranger Station |
| Apartment Building at 116 Spruce Street |
| Apgar Fire Lookout |
| Appleton House No. 13 |
| Appleton House No. 9 |
| Armour Cold Storage |
| Arvon Block |
| Atlantic Hotel |
| Ayers House |
| Baatz Block |
| Babb-Piegan, Montana, Inspection Station |
| Babcock Theatre Building |
| Bader-Jaquette and Westwang Houses and Rental Property |
| Baker and Lovering Store |
| Baker Hotel |
| Baldwin Building |
| Baldwin House |
| Barich Block |
| Barnett, R. T., and Company Building |
| Barrett Hospital |
| Barrett, Martin, House |
| Bartlett, Jack, House |
| Basin Creek Park Historic District |
| Bass Mansion |
| Beall Park Community Center |
| Beaman House |
| Bean, Daniel V., House |
| Beavertown Historic District |
| Beck, Alice, Cabin |
| Bedard House |
| Belgrade City Hall and Jail |
| Bellows House |
| Belly River Ranger Station Historic District |
| Belmont Hotel |
| Belt Commercial Historic District |
| Belton Chalets |
| Bestwick's Market |
| Bethany Lutheran Church |
| Bielenberg, Nick J., House |
| Big Arm School |
| Big Timber Town Hall |
| Billings Chamber of Commerce Building |
| Billings Communal Mausoleum |
| Billings Historic District |
| Billings Old Town Historic District |
| Billings West Side School |
| Billsborough House |
| Birch Creek CCC Camp |
| B-K Ranch |
| Blackmore Apartments |
| Blackstock Residence |
| Blewett, John, House |
| Blood, Oliver, House |
| Blue Front Rooming House |
| Bohart House |
| Boles, Charles, House |
| Bones Brothers Ranch |
| Bonnell, Oliver and Lucy, Gothic Arch Roofed Barn |
| Bon Ton Historic District |
| Bookman, J. A., General Store |
| Bottler, Frederick and Josephine, House |
| Boulder Hot Springs Hotel |
| Boulder Point Lookout |
| Bowman Lake Patrol Cabin |
| Boyd's Shop |
| Boyum, John, House |
| Bozeman Armory |
| Bozeman Brewery Historic District |
| Bozeman Carnegie Library |
| Bozeman National Fish Hatchery |
| Bozeman Sheet Metal Works |
| Bozeman YMCA |
| Brandenburg House |
| Brannin Ranch |
| Branscombe Automobile Machine Shop |
| Brice Apartments |
| Bridger Arms Apartments |
| Bridger Coal Company House |
| Bridger Opera House |
Data from United States Park Service and Wikidata
