Fentress is on the San Marcos River at the southwestern edge of Caldwell County. A settlement, first called Riverside, began developing there in the vicinity of a Cumberland Presbyterian church established in 1869. A horse-powered cotton gin was built in the vicinity about 1870 by the partnership of Cullen R. Smith and Joseph D. Smith. The enterprise was moved to the riverfront and converted to waterpower in 1879; it was operated by family members until it closed in 1968. In 1892 the community was renamed Fentress in honor of James Fentress, its first doctor; he was also a large landholder and a participant in the battle of Plum Creek. A year later a post office was established in W. A. Wilson's general store, with Wilson as postmaster. The community was then on the daily mail route between Luling and San Marcos. A one-room school, which operated for three months each year, opened in 1895. An 1896 business directory lists a doctor, a blacksmith, and a population of 150 in Fentress. The Fentress Waterworks was established in 1898 and a lighting system in 1902. The Fentress Telephone Company was formed soon after 1900, and around 1904 the community had its own newspaper, the Fentress Indicator. In 1905 a Methodist congregation was organized, and four years later they built their own church. In 1907 the one-room school was replaced with a two-room structure that served until 1922, when a two-story, five-room facility with an auditorium was completed. A 1915 business directory lists Fentress with 300 residents, three general stores, a mercantile company, a meat market, a confectionery, a pharmacy. a gin, and a blacksmith shop.
In 1915 Josh Merritt and his partner C. E. Tolhurst created a resort with a swimming and camping facility that offered bathhouses, a water slide, and screened tents with wooden floors. Two years later Merritt and Tolhurst sold the resort to the partnership of J. C. Dauchy, W. R. Smith, and J. M. Dauchy. The new owners added a maple-floored skating rink, where, on alternating nights, dancing was permitted. This move aroused controversy among church members in surrounding communities. In 1918 the six-year-old Fentress water tower collapsed onto the town's only bank; cashier J. W. Lipscomb saved his life by dashing into the vault. This high water mark in Fentress history was viewed by some as divine judgment. For four decades, beginning in the 1920s, nearby oilfield activity was significant in the local economy, and Fentress grew to a peak of 500 residents in 1929. By 1940, however, the population had slipped to 250. The local school was closed in a merger with the Prairie Lea school district in the 1940s. By the early 1990s most of the businesses had disappeared. Even the Fentress Hog Farm, once noted for supplying the performing pigs at Aquarena Center, no longer existed. In 1990 another riverside recreation facility attracted campers and tubers. A nearby landing strip provided an operating base for area skydivers. Otherwise, two businesses, two churches, and a post office were all that remained. Fentress reported a population of eighty-five in 1990. In 2000 the population was 291. The town of Fentress served as the setting of The Evolution of Calpurnia Tate, which won the 2010 Newberry Honor Award.