Deepest Lakes in Wisconsin: Top 25 Ranked by Depth (2026)
Wazee Lake in Jackson County is the deepest natural inland lake in Wisconsin at 350 feet. Below: the 25 deepest monitored Wisconsin lakes ranked by maximum depth, with water quality grade for each.
Top 25 Deepest Lakes in Wisconsin
Ranked by maximum recorded depth (feet).
- 1. Wazee Lake — 350 ft (Jackson County, Grade A)
- 2. Green Lake — 236 ft (Green Lake County, Grade B)
Why Wisconsin Has Deep Lakes
Wisconsin's deepest lakes cluster in two regions: the Northwoods (Vilas, Oneida, and Forest Counties) where Wisconsin glaciation left deep kettle lakes, and a few large kettle lakes in the eastern part of the state — most famously Green Lake.
Depth allows thermal stratification in summer, which preserves cold, oxygen-rich bottom water — the habitat trout and lake whitefish need. Most Wisconsin lakes deeper than 60 feet support coldwater species.