Goodlettsville is a city in Davidson and Sumner counties, Tennessee. Goodlettsville was incorporated as a city in 1958 with a population of just over 3,000 residents; in 2020 the population was 17,789.The northern half of the city is in Sumner County, while the southern half is in Davidson County. In 1963, when the city of Nashville merged with the government of Davidson County, Goodlettsville chose to remain autonomous.