Massachusetts - Role: Building
| Old Town Hall |
| Old Town Hall |
| Old Town House |
| Old Weir Stove Company |
| Old West Church |
| Oliver House |
| Olmsted, Frederick Law, House, National Historic Site |
| Olmsted-Hixon-Albion Block |
| Olney Cook Artisan Shop |
| Opposition House |
| Orange Armory |
| Orchard House |
| Original Congregational Church of Wrentham |
| Orlando |
| Orne, Sarah, House |
| Orrock, Rev. John, House |
| Osborn, Benjamin, House |
| Osborne, Prince, House |
| Osborn House |
| Osborn Street School |
| Osgood Bradley Building |
| Osgood, Col. John, House |
| Osgood Farm |
| Osgood, Samuel, House |
| O'Shea Building |
| Osterville Baptist Church |
| Otis Company Mill No. 1 |
| Otis, (First) Harrison Gray, House |
| Otis, (Second) Harrison Gray, House |
| Otis-Wyman House |
| Our Lady of Good Voyage Church |
| Our Mother of Sorrows Monastery and Retreat Center |
| Oxford School |
| Oxford, The |
| Packard, Moses, House |
| Paddock Farm |
| Page, Christopher, House |
| Page, H. P., House |
| Page, Nathaniel, House |
| Page, Thomas D., House |
| Paine-Dodge House |
| Paine Estate |
| Paine Furniture Building |
| Paine, Robert Treat, Jr., House |
| Paine, Timothy, House |
| Palmer Island Light Station |
| Palmer Memorial Hall |
| Palmer School |
| Park Building |
| Parker-Burnett House |
| Parker, Capt. Nathaniel, Red House |
| Parker, Edmund, Jr., House |
| Parker, Harrison, Sr., House |
| Parker House |
| Parker House |
| Parker House |
| Parker House |
| Parker, James, House |
| Parker, Joseph, House |
| Parker, Samuel, House |
| Parker, Stillman, House |
| Parker Tavern |
| Parker, William, House |
| Parkhill Mill |
| Park Lodge |
| Parkman, Francis, House |
| Parkman Tavern |
| Park Street Firehouse |
| Park Street Railroad Station |
| Parsonage, The |
| Parsons, Edward, House |
| Partridge, Jabez, Homestead |
| Partridge, John, House |
| Patch, Emeline, House |
| Patton and Loomis Block |
| Patton Building |
| Paull, Alfred, House |
| Pawtucket Congregational Church |
| Peabody Central Fire Station |
| Peabody City Hall |
| Peabody Court Apartments |
| Peabody, George, House |
| Peabody Institute |
| Peabody Institute Library |
| Peabody, John P., House |
| Peabody Museum of Salem |
| Peabody School |
| Peabody, The |
| Peabody-Williams House |
| Peak House |
| Pearl Street School |
| Pearson, Abiel, House |
| Peck-Bowen House |
| Peck, John M., House |
| Peirce, Edward, House-Henderson House of Northeastern University |
| Peirce-Nichols House |
| Peirce School |
| Pembroke Friends Meetinghouse |
| Penniman, Edward, House and Barn |
| Pequoig Hotel |
Data from United States Park Service and Wikidata
