All Names
- Page, Robert Morris, 1903-
- Palmedo, Philip F.
- Palmer, Erastus Dow, 1817-1904
- Pan American Sanitary Bureau
- Pannaggi, Ivo
- Parker, Joseph O., 1908-
- Parking Stores, Inc. (2)
- Parks, Joseph A. (Joseph Algernon), b. 1889 (4)
- Partridge, Seymour T. (2)
- Patterson, Eleanor Medill, 1881-1948
- Patterson, Ralph D.
- Peary, Josephine Diebitsch
- Peary, Robert E. (Robert Edwin), 1856-1920
- Pederson, Erling H. (2)
- Peets, Elbert, 1886-1968
- Pelli, Cesar (2)
- Pelz, Paul J., 1841-1918 (3)
- Pennsylvania Central Airlines
- Peoples Drug Stores, inc. (5)
- Pepper Associates (2)
- Pepsi-Cola Company
- Perez, Vincent
- Perkins, George B.
- Perry, Shaw & Hepburn (8)
- Peter A. Juley & Son (2)
- Peter, Martha Parke Custis, 1777-1854
- Peter, Thomas, 1769-1834
- Peter, Walter G. (Walter Gibson), 1868-1945
- Peter, Walter G. (Walter Gibson), 1908-1971
- Peters, William Wesley
- Petersen, Carl August, 1893-1982 (18)
- Peterson, Charles E. (Charles Emil), 1906-2004.
- Peyser, Julius I., b. 1875
- Phi Gamma Delta
- Phifer, Eugene H. (2)
- Phillips & Canby
- Phillips, Canby & Fuller (4)
- Phillips, Thomas W., b. 1874 (5)
- Pierson & Wilson (2)
- Pinchot, Gifford, 1865-1946
- Pinchot, James Wallace (2)
- Pitt, Edward Morris, 1905-1969
- Pleadwell, Theodosia Wallace
- Plowman, Thos. M. (Thomas M.)
- Poe, O. M. (Orlando Metcalfe), 1832-1895 (2)
- Poor, Alfred Easton, 1899-1988 (5)
- Poor, Swanke, Hayden, and Connell
- Pope & Kruse (Wilmington, Del.) (3)
- Pope, John Russell, 1874-1937 (3)
- Pope, John, 1770-1845
- Porter and Lockie
- Postell, James Christopher, 1958-
- Potomac Electric Power Company (8)
- Potts, L. P. (Leslie P.) (3)
- Presbyterian Home (Washington, D.C.) (2)
- President's Council on Pennsylvania Avenue (U.S.)
- Preston, William Gibbons, 1842-1910
- Price and McLanahan
- Price, Bruce, 1845-1903
- Price, H. Brooks
- Prior, L. (Laurens) (2)
- Proctor, Frank B. (Frank Baker), 1893-1956
- Protopapas, Archie, 1896-1959
- Providence Hospital (Washington, D.C.) (2)
- Public Schools of the District of Columbia
- Putnam, G. R. (George Rockwell), b. 1865
- Pyle, Frederic B., 1867-1934 (6)
- Pyle, Howard, 1853-1911 (3)
