Schroon Lake is a 4,105-acre lake about nine miles long in the Adirondack Park, lying mostly in the town of Schroon in Essex County and extending south into Warren County. The Schroon River, a tributary of the Hudson, flows in at the north end and out at the south, and links the lake with nearby Paradox Lake. The hamlet of Schroon Lake sits at the northern end along US Route 9 and has drawn summer visitors since the late 1800s, when steamers carried guests up the lake to its resorts. The lake reaches a depth of 152 feet, and the roads around it form the course of the Adirondack Marathon each September.