[3] The park contains an original adobe structure called El Cuartel, which is the second oldest surviving building in California;[4] only the chapel at Mission San Juan Capistrano, known as "Father Junípero Serra's Church", is older.

The main portion of the site is across the street from the Santa Barbara city Post Office, and is about two blocks from city hall, De la Guerra Plaza and two other museums, the Santa Barbara Historical Museum and the Casa de la Guerra and includes a reconstructed quadrangle with soldiers' quarters and a chapel.

Only two portions of the original presidio quadrangle survive to this day: a remnant of the Cañedo Adobe, named for José María Cañedo, the Soldado de Cuera to whom it was deeded in lieu of back pay when the Presidio fell to inactivity, and the remnants of a two-room soldiers quarters, called El Cuartel.

[6] The Cañedo Adobe is currently serving as the visitor's center for the state park, and El Cuartel is largely unmodified.

Perceiving that the coast at Santa Barbara was vulnerable to attack, he located a spot near a harbor which was sheltered from severe storms.

[9] By the next year, a temporary facility had been completed, and a wheat field planted by the local Chumash Indians of Chief Yanonalit.

[11] The chapel in the Presidio was the primary place of worship for the residents of early Santa Barbara, until its destruction by the 1857 Fort Tejon earthquake.

The mission, located a mile and a half inland, was mainly intended for use by the native Chumash (Barbareño) neophytes after their conversion to Catholicism.

At the time of the Mexican–American War in Alta California, very little of the fortress remained in usable condition,[9] and on December 27, 1846, John C. Frémont ascended San Marcos Pass during rainy weather and came up on the Presidio and the town from behind.