There are 15 Catholic dioceses in Texas. The capitol of Texas, Austin, is in the Diocese of Austin. 

The largest  Roman Catholic diocese in Texas is the Archdiocese of Galveston-Houston. It serves more than 1.7 million Catholics in 10 counties. The Archdiocese of Galveston-Houston is the fifth largest in the United States.

My intention is to visit all 15 dioceses.