All - Architectural style - Gothic Revival
| New York State Armory |
| New York State Inebriate Asylum |
| Niagara Engine House |
| Nicholson-Rand House |
| Niotaze Methodist Episcopal Church |
| No. 8 Thomas Street Building |
| Noftzger-Adams House |
| Nordre Trefoldegheds Menigheds |
| Norlands, The |
| Norman Apartment Building |
| North Point Water Tower |
| North Presbyterian Church |
| Northside United Methodist Church |
| Northwest Texas Hospital School of Nursing |
| Norway Lutheran Church and Cemetery |
| Norwegian Evangelic Lutheran Church and Cemetery |
| Norwood Building |
| Nuestra Senora de Lourdes Chapel |
| Oak City Christian Church |
| Oak Grove Cemetery |
| Oak Hill Cemetery Chapel |
| Oak Hill Cottage |
| Oakland Cemetery Chapel and Superintendent's House and Office |
| Oakland Presbyterian Church |
| Oaklands |
| Oak Lawn Farm Dairy Barn |
| Oak Lawn Methodist Episcopal Church, South |
| Oakley |
| Oakwood |
| Octagon House |
| Odd Fellows Building |
| Ohabei Shalom Cemetery |
| Old Bnai Zion Synagogue |
| Old Cambridge Baptist Church |
| Old Christ Church |
| Old Episcopal Manse |
| Old First Reformed Church |
| Old Fort House |
| Old Gothic Barns |
| Old Holy Redeemer Catholic Church |
| Old Homestead |
| Old Louisiana State Capitol |
| Old Main, Bethany College |
| Old Marine Hospital |
| Old Presbyterian Theological Seminary |
| Old Red Mill and Mill House |
| Old Runnymede Church |
| Old School Presbyterian Church |
| Old Slave Mart |
| Old South Church in Boston |
| Old State Capitol |
| Old St. Luke's Episcopal Church |
| Old Stone Church |
| Old St. Patrick's Cathedral Complex |
| Olive Branch Missionary Baptist Church |
| Olive Chapel African Methodist Episcopal Church |
| Oregon High School |
| Osceola Town Hall |
| Osterling, Frederick J., Office and Studio |
| O Street Market |
| Otis House |
| Otter Lake Community Church |
| Ottumwa Cemetery Historic District |
| Our Lady of Limerick Catholic Church |
| Our Lady of Loretto Roman Catholic Church and Cemetery |
| Our Lady of Peace Cathedral |
| Our Lady of Peace Catholic Church |
| Our Lady of Sorrows Chapel |
| Our Lady of the Ozarks Shrine |
| Our Lady of Victory Academy |
| Overfelt-Campbell-Johnston House |
| Owensville Historic District |
| Paddock Arcade |
| Paine House |
| Paint Lick Presbyterian Church |
| Pan American C.M.A. Church |
| Panna Maria Historic District |
| Pansy Methodist Church and School Historic District |
| Parker, Thomas A., House |
| Parkhurst |
| Park View School |
| Partridge, Edward and Elizabeth, House |
| Pataskala Presbyterian Church |
| Pataskala United Methodist Church |
| Patch, Edith Marion, House |
| Payson Presbyterian Church |
| Peace Baptist Church |
| Peak, Henry C., House |
| Peck, Thomas, Farmhouse |
| Pelton House |
| Pelzer Presbyterian Church |
| Pensacola Hospital |
| People's African Methodist Episcopal Zion Church |
| Perkins Estate |
| Perrin, William, House |
| Perry Hill |
| Perry-Spruill House |
| Perry, T. B., House |
| Pershing, Gen. John J., Boyhood Home |
| Peru Community Church |
Data from United States Park Service and Wikidata
