La Casa Primera de Rancho San Jose is a historic adobe structure built in 1837 in Pomona, California.

It is the oldest home located in the Pomona Valley and in the old Rancho San Jose land grant.

In 1837, Mexican Governor Juan Bautista Alvarado granted the land to Ygnacio Palomares and Ricardo Vejar.

The well provided an ample supply of water, allowing Francisco to plant the area with orange trees, some of which were still thriving in the 1970s.

"[4] At that time, the home consisted of four bedrooms, two baths, a dining room, three fireplaces and a pool on 1.7 acres (6,900 m2).

[5] Hoping to preserve the Casa Primera, the Historical Society of Pomona Valley raised funds to purchase the property for a price up to $80,000.