The Cos House is a historic adobe residence located in La Villita, San Antonio's old riverside neighborhood, that functioned as an ordinary dwelling in the Mexican-era town before becoming associated with a pivotal Texas Revolution event. In December 1835, the house is traditionally identified as the site where Mexican General Martin Perfecto de Cos, commander of the besieged garrison at San Antonio de Bexar, negotiated and signed the terms of surrender to Texian forces, ending the Siege of Bexar and forcing Mexican troops to withdraw from Texas. Before and after that episode, the structure served the everyday function of a private residence for La Villita's Mexican and Tejano residents, part of the informal riverside settlement that grew up near the presidio and mission complex. The building's simple adobe construction and modest scale reflect ordinary domestic use typical of the period rather than any official or military design. In the twentieth century the house was restored as part of a broader Depression-era rehabilitation of La Villita into a historic arts and crafts village. Today the Cos House no longer serves a residential function; it is preserved as a historic landmark within the La Villita Historic Arts Village, used to interpret the Siege of Bexar's surrender and the neighborhood's early Tejano residential history for visitors, and it periodically hosts community and cultural programming tied to La Villita's role as a public arts district.