The Casa Alvarado is located on a portion of the 22,000-acre (8,900 ha) Rancho San Jose granted to Ygnacio Palomares and Ricardo Vejas in 1837.

[3][5][6][7] The Alvarado's adobe living room was also the site of the first public school classes in the Pomona Valley, starting in 1870 or 1871.

[5] Alphonse was born in Pomona and a descendant of Ricardo Vejar, who in 1837 was the co-grantee of the Rancho San Jose along with Ygnacio Palomares.

[5] Isabel was also the descendant of Spanish settlers and had served as the president of the Historical Society of Pomona Valley and the editor of the official publication of the Native Sons and Daughters of the Golden West.

Though designated as a historic site, the Casa Alvarado remains a private home and is not open to the public.