In 1849, a Swiss merchant named Cesar Monod purchased a tract from Castro and and adjoining lot from Michael Simon the following year. Monod was aware of the number of travelers along the San Antonio-El Paso Road and felt he could capitalize on their need for provisions. He built a large one-story house, which included a dry good store.
Irish merchant, John Vance, purchased the house and property only a few years later on February 23, 1853. Knowing that travelers need more than just provisions, he added a second story and expanded the first floor, in order to turn the house into the Vance Hotel. He then built his own family residence between the hotel and the Medina River. In the 1860s he added a two-story bathhouse in the courtyard, which was the only man-made bath between San Antonio and Eagle Pass at the time.
Vance sold a piece of the property along the Medina River in 1854 to partners, George L. Haass and Laurent Quintle. They used the land to build a two-story stone gristmill. The mill went through several hands and a modernization process but continued working into the 20th century.
In 1925, Jordan T. Lawler acquired the hotel, house, mill, and surrounding outbuildings. He converted the mill into a power plant, which gave Castroville its first electric power. The entire land was donated to the state in 1974. Following renovations, the area opened as a historic site in 1981. Today guests can make day trips or stay overnight in the Landmark Inn's bed and breakfast.