The Ruiz House, or Casa de Ruiz, was a Spanish colonial-era residence built around 1745 that originally stood at 420 Dolorosa Street facing Military Plaza in San Antonio, one of the city's oldest surviving domestic structures from the colonial period. Constructed of plastered rubble stone with limestone corner blocks in traditional Spanish-Colonial fashion, the house served as an ordinary family dwelling; by about 1760 it was home to Juan Manuel Ruiz, a tailor who had immigrated from Spain, and later to his son, Jose Francisco Ruiz, who became a prominent Texas patriot and one of only two native-born Texans to sign the Texas Declaration of Independence. Beyond its residential use, the house also functioned briefly as an early educational site: Jose Francisco Ruiz converted its front room into a classroom, reportedly establishing the first school in San Antonio and serving as the city's first official schoolmaster. As San Antonio's Military Plaza area developed and the original building deteriorated, the structure was dismantled, relocated, and reconstructed on the grounds of the Witte Museum in July 1943, where it survives today. In its current form the house no longer serves as a residence or school but functions as a preserved architectural exhibit within the museum complex, illustrating everyday domestic life and early education in Spanish colonial San Antonio for visitors with paid museum admission.