O'FARRELL, TEXAS. O'Farrell is on Farm Road 995 nine miles west of Atlanta in northern Cass County. It was settled in the 1870s, and a post office was established there in 1886 and remained in operation until 1905. In 1890 the community had a post office and store run by W. S. Thompson, with a Baptist church and cemetery nearby. By 1896 it included two stores, a gin, and the church. The first population estimates for the town were recorded in the 1940s, when it had two rated businesses and a population of forty. In 1983 O'Farrell had a church, a cemetery, a town hall, and a population estimated at twenty. Its population continued to be reported at twenty in 1990 and 2000.