Atwell, in eastern Callahan County, was established in the 1870s. Pioneer settlers in the community included Tobie Bell, Uncle Johnny Surles, J. T. Purvis, J. P. Hutchins, and Frank Abbott. Several families moved to the community in 1885 and 1886. Around 1886, residents established a school first named Bell Branch and later Flag Springs. In 1899 a post office was established in the settlement and named for William H. Atwell, district attorney of the Federal District Court of Northern Texas. By 1905 the community had several stores, three churches, a blacksmith shop, and a gin. But the population declined rapidly after 1915, and on June 29, 1929, the post office was discontinued. Atwell's population was listed as sixty-five from 1925 to 1948, after which no further estimates were available until 2000, when the population was eight.