The Guide to the History of Texas (Ref. Z1339 .G84 1988) takes a fairly detailed look at the holdings, as of 1988, of the following Texas archives:
Special Collections, University of Texas at Arlington
Eugene C. Barker Texas History Center, University of Texas at Austin (Center for American History)
Nettie Lee Benson Latin American Collection, University of Texas at Austin
Lyndon Baines Johnson Presidential Library and Museum, Austin
Texas State Library, Austin
Research Center, Panhandle-Plains Historical Museum, Canyon
Sterling C. Evans Library, Texas A&M University, College Station
Texas/Dallas History and Archives Division, Dallas Public Library
Special Collections, University of Texas at El Paso Library
National Archives--Fort Worth Branch
Houston Metropolitan Research Center, Houston Public Library (Clayton Library)
Woodson Research Center, Fondren Library, Rice University, Houston
Southwest Collection, Texas Tech University, Lubbock
Special Collections Dept., Ralph W. Steen Library, Stephen F. Austin State University (Nacogdoches)
Special Collections Department, the University of Texas at San Antonio
It also briefly mentions 24 other archives, including those at the Texas General Land Office and the Catholic Archives of Texas.