Plaque and site are located in a locked park. Access only during operating hours.
From the Guidebook:
The oldest portion of the
adobe was built about 1834 by ex-mission Indians. It was
enlarged by Eulogio de Celís in 1846, and an upper
story added by Rómulo Pico in 1874. The house was
restored by Mr. and Mrs. M. R. Harrington in 1930.