La Grange is a home rule-class city in Oldham County, Kentucky, in the United States. The population was 10,067 at the time of the 2020 U.…La Grange is a home rule-class city in Oldham County, Kentucky, in the United States. The population was 10,067 at the time of the 2020 U.S. census. It is the seat of its county. A unique feature of the city is the CSX Transportation street-running mainline track on Main Street that sees multiple trains in both directions.