A two-storey 1860 adobe-and-fired-brick ranch house built by John Rains, who married into the property when he wed Maria Merced Williams of the original Mexican land-grant family. The house is one of the earliest American-era ranch buildings in the Inland Empire — built in the brief boom period when Anglo cattle ranchers were taking over the old ranchos — and the only one still surviving in its original location.
The house is run as a museum by the San Bernardino County Museum, furnished in period style with original Rains-family pieces, and surrounded by a restored garden of date palms and grapevines. Guided tours are given on weekend afternoons. National Register of Historic Places.