Indiana - Criteria: A (event)
| Myrtle Fern |
| Nappanee West Park and Pavilion |
| Nappaness Eastside Historic District |
| Narrows Bridge |
| Neet Bridge |
| Nester House |
| Nevins Bridge |
| New Albany Downtown Historic District |
| New Albany National Cemetery |
| New Augusta Historic District |
| Newberry Friends Meeting House |
| New Carlisle Historic District |
| New Castle Commercial Historic District |
| New Goshen District No. 2 School |
| New Harmony Historic District |
| New Hope Bridge |
| Newport Covered Bridge |
| Newsom-Marr Farm |
| Newton County Courthouse |
| New York Central Railroad Passenger Depot |
| New York Chicago and St. Louis Railroad Steam Locomotive No. 765 |
| Nicholson, Andrew, Farmstead |
| Nike Missile Site C47 |
| Ninth Street Hill Neighborhood Historic District |
| Noble County Courthouse |
| Noblesville Commercial Historic District |
| Normain Heights Historic District |
| Normal Hall |
| Norris Farm-Maxinkuckee Orchard |
| North Anthony Boulevard Historic District |
| Northern States Life Insurance Company |
| North Irvington Gardens Historic District |
| North Liberty Commercial Historic District |
| North Liberty Park |
| North Manchester Historic District |
| North Manchester Public Library |
| Northside Boulevard Riverwall |
| North Vernon Downtown Historic District |
| North Wabash Historic District |
| North Washington Street Historic District |
| Northwood Historic District |
| Oakdale School |
| Oak Hill Cemetery |
| Oaklandon Historic District |
| O'Brien Electric Priming Company |
| Ohio Boulevard-Demming Park Historic District |
| Ohio Street Bridge |
| Old Courthouse (Second St. Joseph County Courthouse) |
| Old Crescent, The |
| Oldenburg Historic District |
| Olde Store (John O'Ferrell Store) |
| Old Fellwock Auto Company |
| Old Frankfort Stone High School |
| Old Greencastle Historic District |
| Old Hoosier Theatre |
| Old Jeffersonville Historic District |
| Old Newburgh Presbyterian Church |
| Old Northside Historic District |
| Old Pathology Building |
| Old Perry County Courthouse |
| Old Richmond Historic District |
| Old Silk Stocking Historic District |
| Old State Bank |
| Old Vanderburgh County Courthouse |
| Orange County Courthouse |
| Oriental Lodge No. 500 |
| Original Newburgh Historic District |
| Orleans Historic District |
| Orr Iron Company |
| Orr, Robert, Polygonal Barn |
| Otis Park and Golf Course |
| Our Savior Lutheran Church |
| Owen County Courthouse |
| Oxford |
| Oxford Hotel |
| Palace Lodge |
| Palace Theater |
| Palais Royale Building |
| Paoli Historic District |
| Paramount Theater Building |
| Parkview Home of Clinton County |
| Parson and Scoville Building |
| Parsons, A.A., Farmstead |
| Patoka Bridges Historic District |
| Patterson, J.W., House |
| Peabody Memorial Tower |
| Pearl Steam Laundry |
| Pearson, Lora B., School |
| Pearson Terrace |
| Pendleton Historic District |
| Pennslyvania Railroad Station |
| Pennsylvania |
| Pennsylvania Railroad Station |
| Perrin Historic District |
| Peru High School Historic District |
| Phillips Bridge |
| Pierceton Historic District |
| Pike County Courthouse |
| Pike Inn, Old |
| Pinhook Methodist Church and Cemetery |
Data from United States Park Service and Wikidata
