Rios was formed when the post office opened in 1938. The town's first
postmaster was Felipe V. Rios, however the town is believed to have
been named in honor of Calletonio Rios, who settled in the area in
the 1890s. The town has been shown on maps from the 1940s as La Garcia,
Texas but was corrected on maps from the 50s. The population of Rios
during the 1940s was around 75, a figure it has used ever since.