The Republic of the Rio Grande Museum is located in the downtown San Agustín de Laredo Historic District in Laredo, Texas, at 1005 Zaragoza Street. Founded in 1957 by the Laredo Historical Society, the museum is housed in an original sandstone and adobe building built in the 1830s that was once home to prominent rancher and Laredo mayor Bartolomé García and, according to local tradition, served as the capitol building for Mexican Federalist leaders in Tamaulipas, Nuevo Leon, and Coahuila, in their attempt to break away from the Centralist government under the auspices of the newly-proclaimed Republic of the Rio Grande in 1840. Although Laredo was the official seat of the Republic’s government, the leaders of the Republic operated primarily in Guerrero because of an available printing press. After the surrender of Federalist general Antonio Canales Rosillo and the end of the short-lived Republic, the building remained under the ownership of the García family until García’s death in 1878. During this time period, two rooms were added on to the northern and southern walls of the original compound. The building then passed between a number of private owners before being deeded to Laredo National Bank.
From 1918 to 1960 the building was owned by the Laredo Independent School District, which used the adjacent lot as grounds for Laredo High School and the building as a classroom. In 1960 ownership of the museum and the surrounding buildings was sold by Laredo ISD to the Pan-Tex Hotel Corporation for $10,000. Pan-Tex transformed the old Laredo High School into a luxury boutique hotel next to the museum called La Posada and renovated the museum with the assistance of the Laredo Historical Society. The museum opened to the public in February 1962, and on May 15, 1962, it became the first building in Laredo to be presented with a Texas State Historical Survey Committee Historical Building Medallion in a large ceremony in the San Agustín Plaza.
In 1993 the museum and La Posada were purchased by businesswoman and philanthropist Barbara Fasken, and in the 2010s the museum has been maintained through the Webb County Heritage Foundation. Under new ownership, the foundation renovated the museum by removing and replacing old, chipped plaster from the walls, repairing the door framing, and restoring the roof. The main room of the exhibit features a short history of the Republic of the Rio Grande as well as a description of life in Laredo and the surrounding area from 1840 to 1930. The other rooms feature a re-creation of a circa-1830 ranching home using artifacts and materials from the area. Donors to the exhibit include the Nuevo Santander Museum, the Deutz and Phelps Collection, the Sanchez Estate, the Ramon Family, and many more. The museum continues to commemorate the short existence of the Republic of the Rio Grande as well as the local history of Laredo, one of the oldest continuously inhabited settlements in Texas.