Lewis County is a county located in the U.S. state of New York. As of the 2020 census, the population was 26,582, making it the fourth-least populous county in New York. Its county seat is Lowville. The county is named after Morgan Lewis, the Governor of New York when the county was established. The county is part of the North Country region of the state.

Lowville is a village in Lewis County, New York, United States. As of the 2010 census it had a population of 3,470. The village is in the Black River Valley, between the foothills of the Adirondack Mountains and the Tug Hill Plateau, in an area often referred to as the North Country. It is located in the center of Lewis County, in the southeastern part of the similarly named town of Lowville.