[2][3][4] The house was built in 1860–1861 after John Rains purchased the Rancho Cucamonga land grant in 1858 from the Tapia estate.

John Rains was a prominent businessman and socialite who opened California's first commercial winery, and his house hosted lavish parties for other local elites.

Rains' fortunes soon took a turn for the worse, though; he had to mortgage the house after several business failings, and in 1862 he was murdered.

[3] To better recognize the importance of María Merced Williams to the site's history, the San Bernardino County Board of Supervisors voted on June 28, 2022 to change the name of the site to the María Merced Williams and John Rains House.

This article about a property in San Bernardino County, California on the National Register of Historic Places is a stub.