Lake Pepin is the widest natural stretch of the Mississippi River — 28 miles long and up to 2.5 miles wide, formed by the delta fan of the Chippewa River backing up the Mississippi's flow. It is large enough to have genuine whitecaps in a stiff wind, which makes it popular with sailors and gives it the feel of an inland sea rather than a river.
In summer, the lake is busy with sailboats, fishing boats, and kayakers. The public beach at Pepin is modest but functional. Bald eagles are common year-round — they fish the open water and nest in the bluffs above the river. In winter, ice fishing shanties cluster on the frozen surface, and conditions occasionally allow ice boating.
The lake forms the natural western boundary of the village. The harbor has transient docking for boats arriving from the Mississippi system.