 By 1850, it was the second-most populous county in Texas of the 78 counties that had been organized at that time, according to the 1850 census.Rusk County's population was 8,148 then; it was surpassed only by Harrison County with 11,822 people.With the discovery of oil in Joinerville in October 1930, an oil boom began that caused county population to nearly double during the next decade, and caused dramatic changes in the county towns.