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; at the 2010 census, the city had a total …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; at the 2010 census, the city had a total population of 15,921 and in 2020 the population was 17,789.