Williams grew its population 5.9% between July 2017 and July 2018, while Ward County’s population fell 1%, according to the estimates. Among counties of 20,000 population or more, Williams also led the nation, with its oil-boom growth of 57.8% from 2010 to 2018 boosting its population to 35,350. Ward County grew 9.8% over that time, leaving the population at an estimated 67,744 in July 2018.