San Antonio's five Spanish colonial missions, including what became known as the Alamo, were built between 1718 and 1731 specifically to convert the local Coahuiltecan peoples, and their original religious purpose did not survive Mexican independence. Secularization began as early as 1793, when San Antonio de Valero, the mission that later became the Alamo, was the first to be formally secularized under a Spanish crown order, its remaining religious functions ended and its lands opened to distribution among settlers. The rest of the San Antonio missions followed more gradually, and the process concluded under the newly independent Mexican government, which by 1824 had transferred the missions' remaining lands, buildings and assets fully into secular parish and private hands, ending, roughly a century after Father Antonio Olivares founded the first of them, the evangelizing purpose the whole mission system had originally existed to serve. The buildings survived that transition and today form the largest concentration of intact Spanish mission architecture in the country, a UNESCO World Heritage site whose current religious use, several remain active Catholic parishes, postdates the mission era that built them by more than a century.
Texas's German and Czech immigrant communities built distinctive painted Lutheran and Catholic churches still standing in Hill Country towns like Fredericksburg, and the state's rapid growth has since produced some of the country's largest megachurches, including Lakewood Church in Houston. Evangelical Protestant identification leads at twenty seven percent of adults, per Pew's 2023-24 study.