Texas - Area of significance: Architecture
| Navy Park Historic District |
| Neal House |
| Near Northside Historic District |
| Neathery, Sam, House |
| Neese, William, Sr., Homestead |
| Neill-Cochran House |
| Nelson Farmstead |
| Nenney, J. P., House |
| Neuhaus, C. L., House |
| Neuhaus, Hugo V., Jr. House |
| Neumann, William, House |
| Newberry, J. J., Company |
| Newman, I.M. and Margaret, House |
| Newsome-King House |
| Newsome, R. F., House |
| Newsom-Moss House |
| Newton County Courthouse |
| Newton House |
| Newton, William Walter, House |
| Nienstedt, Herbert, House |
| Nienstedt, William, House |
| Nolte-Rooney House |
| North Bishop Avenue Commercial Historic District |
| Northcutt House |
| North Fort Worth High School |
| Northgate Site |
| North Rogers Street Historic District |
| North Side Historic District |
| Northwest Texas Hospital School of Nursing |
| Norton-Orgain House |
| Norway Mill |
| Norwood Building |
| Noto House |
| Novy, Joe, House |
| Nueces County Courthouse |
| Nuestra Senora del Espiritu Santo de Zuniga Site |
| Nuggett Hill Historic District |
| Number 4 Hook and Ladder Company |
| Oakdale Park |
| Oakes Hotel Building |
| Oakhurst Historic District |
| Oak Lawn Methodist Episcopal Church, South |
| Oakwood Cemetery Annex |
| Oakwood Cemetery Historic District |
| Oblate Park Historic district |
| O'Bryne, John and Eva, House |
| O'Connor-Proctor Building |
| O'Connor, Thomas M., House |
| Ogle, Joseph, House |
| Old Beer and Ice Warehouse |
| Old Bnai Zion Synagogue |
| Old Brazoria County Courthouse |
| Old Brownson School |
| Old Brulay Plantation |
| Old Bryant-Link Building |
| Old Continental State Bank |
| Old Federal Building and Post Office |
| Old Federal Building-Federal Courthouse |
| Old Frio County Jail |
| Old Galveston Customhouse |
| Old Georgetown High School |
| Oldham Avenue Historic District |
| Oldham, Mary and Frank House |
| Old Hidalgo Courthouse and Buildings |
| Old Hidalgo School |
| Old Houston National Bank |
| Old Land Office Building |
| Old Lone Star Brewery |
| Old McCulloch County Jail |
| Old Mercantile Building |
| Old Morris County Courthouse |
| Old Municipal Assembly Hall |
| Old Nacogdoches University Building |
| Old Nazareth Academy |
| Old Pierce House |
| Old Reagan County Courthouse |
| Old Rock Saloon |
| Old San Francisco Historic District |
| Old Sherman Public Library |
| Old Sixth Ward Historic District |
| Old St. Anthony's Catholic Church |
| Old St. Luke's Episcopal Church |
| Old Town Historic District |
| Old Town Residential Historic District |
| Old U.S. Post Office and Courts Building |
| Old Victoria County Courthouse |
| Old West Austin Historic District |
| Old West Texas Utilities Company |
| Old Wooten, H. O., Grocery |
| Oliphant House |
| Oliphant-Walker House |
| Olive, L. W., House |
| Oliver-Eakle-Barfield Building |
| Olive Street Historic District |
| Olson-Hanson Farm |
| Olson, Joseph and Anna, Farm |
| Olson-Nelson Farm |
| One Main Place |
| Onion Creek Post Office and Stagecoach House |
| Orgain, Elbert S., House |
Data from United States Park Service and Wikidata
