All - Constructed - 1870–1879
| Abbot Hall |
| Abbotsford |
| Abell Farmhouse and Barn |
| Academy Building |
| Adam-Derby House |
| Adams Academy |
| Adams County Courthouse |
| Adams County Jail |
| Adams Mill Covered Bridge |
| Adams-Pickering Block |
| African Zion Baptist Church |
| Ailsa Farms |
| Albergue Caritativo Tricoche |
| Alcovy Road Grist Mill |
| Alden-Delahanty Block |
| Aldrich, Godfrey, and White Block |
| Alford-Nielson House |
| Alkemeyer Commercial Buildings |
| Allen, Jacob C., House |
| All Saints' Episcopal Church |
| Allsop-Jensen House |
| Alls Souls Church |
| Alms and Doepke Dry Goods Company |
| Alpena Light |
| Alpine Hose Company No. 2 |
| Alston House |
| Amboy Illinois Central Depot |
| American Exchange Bank |
| American Fork Presbyterian Church |
| American Net and Twine Company Factory |
| American Supply Company Building |
| American Watch Tool Company |
| Amos Block |
| Amrita Club |
| Anderson Hall |
| Anderson Homestead |
| Anderson, Marian, House |
| Anheuser-Busch Brewery |
| Appanoose County Sheriff's House and Jail |
| Appin (Boundary Increase) |
| Arch and Ridge Streets Historic District |
| Archbishop Lamy's Chapel |
| Arch Street Opera House |
| Arendt-Seymour House |
| Arlington Coal & Lumber |
| Armijo, Juan Cristobal, Homestead |
| Armijo, Nestor, House |
| Armstrong House |
| Arnett-Fullen House |
| Arnold Arboretum |
| Arnold, Capt. Alexander A., Farm |
| Arnold Print Works |
| Arsenal Hill |
| Art Gallery Building |
| Artz House |
| Arvonia School |
| Ascension Episcopal Church and Rectory |
| Ashland Bridge |
| Ashland Masonic Lodge Building |
| Ashworth and Jones Factory |
| Ashworth, John, House |
| Atchison, Topeka, and Santa Fe Railroad Depot |
| Atherton Bridge |
| Atkins and Smith House |
| Atlanta Historic District |
| Aurora Train Station |
| Au Sable Light Station |
| Averasboro Battlefield Historic District |
| Baasen House-German YMCA |
| Backwards Tunnel |
| Bain Commercial Building |
| Baker, Charles, House |
| Baker, Samuel, House |
| Ballantine, James, House |
| Ball, W. C., House |
| Baltimore City Hall |
| Bangor Elevator |
| Bangs Block |
| Bank Block |
| Banner Elk Hotel |
| Banta, George, Sr. and Ellen, House |
| Baptist Chapel Church and Cemetery |
| Barber, Obediah, Homestead |
| Barker, William, Whiskey Bonding Barn |
| Barnard Mills |
| Barnes House |
| Barron Library |
| Barron, Martin Van Buren, House |
| Bartell House |
| Bartlett House |
| Bartonsville Covered Bridge |
| Bassnett-Nickerson House |
| Bayard School |
| Baystate Corset Block |
| Beaumont Hotel |
| Beckett's Castle |
| Beck House |
| Bedford Building |
| Bedford Depot |
| Beebe House |
Data from United States Park Service and Wikidata
