Wisconsin - Significance region: Local
| Murray-George House |
| Muskego State Graded School |
| Myers-Newhoff House |
| Myers, Peter, Pork Packing Plant and Willard Coleman Building |
| Naeset, Jens, House |
| Nakoma Historic District |
| Nathan Strong Park Historic District |
| National Hotel |
| National Tinsel and Toy Manufacturing Company Building |
| Needham, Enoch Gardner and Mary Caroline Koch, House |
| Neenah United States Post Office |
| Neese, Elbert, House |
| Neillsville Downtown Historic District |
| Neillsville Masonic Temple Lodge No. 163 |
| Neillsville Post Office |
| Neillsville Standpipe |
| Nelson, Charles E., Sr., House |
| Nelson Hall |
| Neosho Village Hall |
| Neufeld, Albert C. and Ellen H., House |
| Newberry Boulevard Historic District |
| New Coeln House |
| New Glarus Hotel |
| New Glarus Public School and High School |
| New Glarus Town Hall |
| Newhall Avenue Pump House and Reservoir |
| New Hope Norwegian Evangelical Lutheran Church and Cemetery |
| New Jersey Building |
| New Richmond Commercial Historic District |
| New Richmond East Side Historic District |
| New Richmond News Building |
| New Richmond Roller Mills Co. |
| New Richmond West Side Historic District |
| New York Block |
| Nichols, Frank Eugene, House |
| Nichols, John T., and Margaret, House |
| Nickell, William, A., House |
| Nicolet Public School |
| Nieman, Edwin J., Sr., House |
| Nishan, Freda Meyers, Memorial Chapel |
| No. 4 Engine House |
| Noble, Alexander, House |
| North 47th Street Bungalow Historic District |
| North Broadway Street Historic District |
| Northern Block |
| Northern Casket Company Building |
| North First Street Historic District |
| North Grant Boulevard Historic District |
| North Main Street Bungalow Historic District |
| North Main Street Historic District |
| North Main Street Historic District |
| North Main Street Historic District |
| North Michigan Street-North Superior Street Historic District |
| North Milwaukee High School |
| North Point North Historic District |
| North Point Water Tower |
| North Sherman Boulevard Historic District |
| Northside Historic District of Cream Brick Workers' Cottages |
| North Third Street Historic District |
| North Washington Street Historic District |
| Northwestern Hotel |
| Northwest Side Historic District |
| North Wisconsin Lumber Company Office |
| Norton, Pearl C., House |
| Norwegian Evangelic Lutheran Church and Cemetery |
| Notre Dame Church and Goldsmith Memorial Chapel |
| Nunn-Bush Shoe Company Factory |
| Nye, Clark, House |
| Oak Creek Parkway |
| Oak Grove Cemetery |
| Oak Hill Cemetery |
| Oakland-Dousman Historic District |
| Oatman Filling Station |
| O'Brien-Peuschel Farmstead |
| Observatory Hill Mound Group |
| Oconomowoc City Hall |
| Oconomowoc Depot |
| Oconomowoc High School |
| Oconto County Courthouse |
| Oconto Main Post Office |
| Octagon House |
| Octagon House |
| Oehler Mill Complex |
| Old Ashland Post Office |
| Old Fourth Ward Historic District |
| Old Iron County Courthouse |
| Old Main Street Historic District |
| Old Ozaukee County Courthouse |
| Old Plover Methodist Church |
| Old Rock School |
| Old Rock School |
| Old Spring Tavern |
| Old St. Mary's Church |
| Old Synagogue |
| Old Waukesha County Courthouse |
| Old World Third Street Historic District |
| Olfson, Peter and Jessie, House |
| Oliver, Joseph B., House |
| Oliver, Owen and Margaret, House |
| Omaha Hotel |
Data from United States Park Service and Wikidata
