The railroad came through in 1872, enabling Crockett to exploit the county's timber resources. By 1885 the town was thriving with a population of 1,200, and the following year a school was opened for black girls. It evolved into Mary Allen Junior College, which operated into the 1970s. In 1904 lignite mining started, peaking about 1910. The stands of timber were seriously depleted by the 1920s. The population was over 3,000 in the mid-1920s, and by 1936 it was nearly 4,500. The population of Crockett increased while most of East Texas declined after World War II. It had reached 5,000 by the 1960 census.