CALLIS, TEXAS. Callis, also known as Oak Grove, was twenty-five miles northeast of McKinney in northeastern Collin County. A post office operated there from 1891 through 1904. By 1900 the community had a population of fifty, two stores, a cotton gin, a church, and a school. Its population stood at twenty-five by the mid-1940s, the last time population statistics were reported.
Roy Franklin Hall and Helen Gibbard Hall, Collin County: Pioneering in North Texas (Quanah, Texas: Nortex, 1975).