Old Town State Park is known as the birthplace of California. In 1821, when Mexico gained independence from Spain, a small group of Mexican settlers began building homes at the foot of the hillside below the first mission and Presidio. Because wood was scarce at the time, sun-dried adobe bricks were used. Thus, the buildings had a different look, a brownish-red color and rough exterior. The first five buildings of Old Town were homes belonging to the Carrillo, Ruiz, Ybanes, Serrano and Marron families and it was these buildings that were considered to be the center of the community. Today, five of these original adobe structures still stand: La Casa de Estudillo, La Casa de Bandini, La Casa de Altamirano Pedrorena and the Mason Street School, San Diego’s first one room schoolhouse. Visitors to Old Town State Park can tour these original buildings which now house restaurants, shops and a museum and offer a taste for the customs, traditions and cuisine of San Diego’s first inhabitants.

In 1868, the San Diego Union, the first newspaper, began its publication in Old Town. The first office of the newspaper is restored as it was when the Union printed its first edition on October 10 of that year. Visitors can see the original print-room and the editor's office.

Between fires, droughts, earthquakes and illnesses, Old Town San Diego was declining throughout the remainder of the 1800’s. Soon all government offices moved to New Town which was established by Alonzo Horton from San Francisco. In 1907, efforts began to restore Old Town, when a sugar plantation owner purchased Casa de Estudillo. During the rest of the early 1900’s buildings were restored and new ones were built to bring back its Spanish influence. In 1968, Old Town San Diego became a State Historic Park and since then, millions of visitors have enjoyed the adventure back to witness the daily lives of its Mexican and early American citizens.