Hamilton County is a county in the U.S. state of New York. As of the 2020 census, the population was 5,107, making it the least populous county in New York. With a land area nearly the size of Delaware, it is the least densely populated county east of the Mississippi River. Its county seat is Lake Pleasant. The county was created in 1816 and organized in 1847. The county is part of the North Country region of the state.

Essex County is a county in the U.S. state of New York. As of the 2020 census, the population was 37,381. Its county seat is the hamlet of Elizabethtown. Its name is from the English county of Essex. Essex is one of only 2 counties that are entirely within the Adirondack Park, the other being Hamilton County. The county is part of the North Country region of the state.