The Texas Ranger Museum in Waco, Texas, is a very interesting place to visit and their website has links to all kinds of valuable information.
From Wikipedia:
“The Texas Ranger Division, commonly called the Texas Rangers, is a law enforcement agency with statewide jurisdiction based in Austin, the capital of Texas, in the United States. Over the years, the Texas Rangers have investigated crimes ranging from murder to political corruption, acted as riot police and as detectives, protected the Governor of Texas, tracked down fugitives, and functioned as a paramilitary force at the service of both the Republic (1836–45) and the state of Texas.
“The Texas Rangers are believed to have been unofficially created by Stephen F. Austin in 1823 and formally constituted in 1835. The unit was dissolved by the federal authorities during the post-Civil War Reconstruction era, but was quickly reformed upon the reinstitution of home government. Since 1935, the organization has been a division of the Texas Department of Public Safety; it fulfills the role of Texas’s State Bureau of Investigation. As of 2009, there are 134 commissioned members of the Ranger force.
“The unit has been called the oldest state-level law enforcement agency in the United States. The Rangers have taken part in many of the most important events of Texas history and were involved in some of the best-known criminal cases in the history of the Old West, such as those of gunfighter John Wesley Hardin, bank robber Sam Bass, and outlaws Bonnie and Clyde. Scores of books have been written about the Rangers, from well researched works of nonfiction to pulp novels, making them significant participants in the mythology of the Wild West. During their long history, a distinct Ranger tradition has evolved; their cultural significance to Texans is such that they are legally protected against disbandment.”
For more information about the rangers you can go to the museum’s website at Texas Ranger Museum.