The small kettle lake that gives Grayslake its name sits within the village limits and is surrounded by a modest park. It's an 80-acre lake formed by a block of glacial ice that melted in place roughly 10,000 years ago, leaving a bowl in the landscape that filled with water. The lake is used for fishing and non-motorised boating, and the surrounding park is popular for picnics and walks.
The lake itself is unremarkable as a tourist attraction, but it gives the town its distinctive character — a genuine lake in the middle of a suburb, with ducks, fishing lines, and the occasional great blue heron. Worth a short walk if you are in the area.