Old Town, San Diego, April 2021. The Johnson House was built in 1870. It was a wood-frame pre-fabricated office building that was brought by ship to San Diego, which was typical of many American buildings in that area at that time. It had a false front and full-length wooden porch. George Alonzo Johnson, a steamboat captain on the Colorado River and owner of the Colorado Steam Navigation Company and of the Rancho Santa Maria de Los Peñasquitos, built the building on a vacant lot on La Plaza de Las Armas, in Old Town, which was purchased from Tomasa Pico de Alvarado, his mother-in-law, in 1869.

A few years after 1880, when the Johnsons lost their rancho to their creditors, they moved into this building on the plaza, where the captain died in 1903.