McMahan's Chapel, organized in 1833, is the oldest Methodist church and the oldest Protestant congregation with continuous services in Texas. The chapel is located on Spur 35 two miles south of Route 21 and twelve miles east of San Augustine. Samuel D. McMahan of Tennessee settled there in 1831 in what was then the San Augustine municipality of the Mexican government (see MEXICAN TEXAS). At the Mississippi Conference in Vicksburg in November 1832, James P. Stevenson was appointed to the Sabine Circuit of Louisiana, a few miles east of where McMahan had settled. In the spring of 1833 at Natchitoches, Louisiana, Stevenson met some Texans who asked him to cross the state line and preach to them, even though Protestant services were forbidden in Mexican territory. Assured by the laymen of protection, Stevenson agreed and held a two-day meeting in a private home near the site of present Milam. McMahan attended the services and invited Stevenson to preach at his home also. Stevenson did so and returned several times during the year to hold services. He was requested to organize a church, but knowing that starting a Methodist church would be against the law, he formed instead a "religious society" of forty-eight members in September 1833. He named McMahan the "class leader." In July 1834 Henry Stephenson, successor of James P. Stevenson on the Sabine Circuit, reorganized the society in McMahan's home, and it was soon called McMahan's Chapel.
After the Texas Revolution the McMahan congregation grew rapidly, and there was need for a church building. In December 1838 the Mississippi Conference appointed Littleton Fowler as presiding elder of the Texas Mission District. Fowler built a home near McMahan's place and made it his headquarters. About 1839 he assisted with the building of a log chapel, forty by thirty feet, for the McMahan congregation. The log structure was replaced by a frame church in 1872, and another of similar material was erected in 1900. The present brick building was dedicated in 1956. The 1970 general conference designated McMahan Chapel as one of the first three official United Methodist landmarks. A cemetery containing the graves of Samuel D. McMahan, Littleton Fowler, and other early Methodist leaders in Texas adjoins McMahan Chapel.