Johnson House, Old Town San Diego, Historical building in Old Town San Diego, United States.

Johnson House is a reconstructed wood-frame building on Plaza de Las Armas in Old Town San Diego, with a false front and a full-length wooden porch. It was prefabricated and shipped to San Diego in 1870, a common practice for American buildings there at the time. It now serves as a park concession.

George Alonzo Johnson, a Colorado River steamboat captain and owner of the Colorado Steam Navigation Company, built the Johnson House in 1870 on a vacant lot on La Plaza de Las Armas. He had bought the lot in 1869 from his mother-in-law, Tomasa Pico de Alvarado. The wood-frame prefabricated office building arrived by ship, a common method for American buildings in the area then. After the Johnsons lost Rancho Santa Maria de Los Peñasquitos to creditors a few years after 1880, they moved into this building, where the captain died in 1903. California State Parks reconstructed it in 1989.

The building is named for George Alonzo Johnson, a Colorado River steamboat captain and owner of the Colorado Steam Navigation Company. After the Johnsons lost Rancho Santa Maria de Los Peñasquitos to creditors a few years after 1880, they moved into this plaza building, where the captain died in 1903. It now operates as a park concession.

The location sits on San Diego Avenue in the heart of Old Town and is easy to reach on foot when walking through the historic area. Visitors should know that opening hours vary depending on when they visit.

Prefabrication was not unusual: the wood-frame building arrived by ship in 1870, as was typical for many American buildings in the area then. George Alonzo Johnson placed it on a vacant lot on La Plaza de Las Armas that he had bought from his mother-in-law, Tomasa Pico de Alvarado, in 1869.