Old Town San Diego preserves the settlement that emerged below Presidio Hill in the 1820s and became the civic and commercial center of early San Diego. Founded nearby in 1769 with the presidio and mission, the community grew during the Mexican period into the region’s governmental and trading hub, gained pueblo status in 1834, and remained the city’s core after California entered the United States in 1850. Its inland location limited access to shipping, and in the 1860s a new harbor-centered district drew activity away. The historic district preserves this transition through adobes, public buildings, workshops, and spaces such as Casa de Estudillo and the plaza.