The rancho includes the original nine-room de la Ossa Adobe, the two-story limestone Garnier building, a blacksmith shop, a natural spring, and a pond.

[2] The natural spring provided a year-round source of water for the ancient village of Siutcanga, home to the Tongva people, for thousands of years.

Located along a significant travel route between Los Angeles and Santa Barbara, the property passed through many hands between the 1840s and the early 20th century.

[6] According to a description from 1875 the main ranch spring "supplied a stone reservoir and a bathing pool and yielded about 5 U.S. gallons (19 L; 4.2 imp gal) a minute".

[7] As of 1969 the springs still yielded 24,000 U.S. gallons (91,000 L; 20,000 imp gal) a day,[9] and they were still flowing at Los Encinos State Historic Park as of 1978.