Leitchfield is the county seat of Grayson County, Kentucky, United States. Leitchfield is a home rule-class city with a population of 6,699 as of the 2010 census.
The town was named for Major David Leitch, an aide to Gen. George Washington and the original owner of much land in the county, including the town site, at the eastern end of his holdings. The city was formally incorporated by the state assembly in 1866.
Leitchfield lies in the Clifty Area, the sandstone-dominated belt that is usually classified as part of the West Kentucky Coal Field but separates the coalfield from the limestone-rich Pennyroyal Plateau. A fault running through the area puts limestone at or near the surface, and there are quarries west of town. The city is located along the Western Kentucky Parkway at the junction of Kentucky Route 259. U.S. Route 62 intersects 259 near the middle of town. Leitchfield is situated between Rough River Lake to the north and Nolin River Lake to the south.
According to the United States Census Bureau, the city has a total area of 10.9 square miles (28.2 km2), of which 10.8 square miles (28.1 km2) is land and 0.04 square miles (0.1 km2), or 0.38%, is water.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Leitchfield has a humid subtropical climate, abbreviated "Cfa" on climate maps.
As of the census of 2000, there were 6,139 people, 2,485 households, and 1,615 families residing in the city.