This New York City based firm was established in 1894 by architects Francis Hoppin (1866-1941) and Terence Koen (1858-1923), who both previously worked as draftsmen and designers in the office of McKim, Mead & White. Hoppin & Koen designed numerous residences and municipal structures in the Beaux-Arts and Colonial Revival styles throughout New York City and the northeast region.
In New York City, the firm designed both grand townhouses and municipal buildings, including the former New York City Police Headquarters in the Little Italy neighborhood. In the Hudson Valley the architects designed municipal buildings, including the Albany County Courthouse in Albany, New York, and residences, including Blithewood in Annandale-on-Hudson, New York (now part of Bard College) and Springwood (now Home of Franklin D. Roosevelt National Historic Site) in Hyde Park, New York.
From 1919 to 1920 Hoppin and Koen worked under Frederick Law Olmsted, Jr., designing multiple Colonial Revival residences for United States Housing Corporation Project # 157 (now United States Housing Corporation Historic District) in New London, Connecticut. The project is considered among the earliest federally-sponsored housing projects in the United States. In 1923 Terence Koen passed away and the firm disbanded.