McLean County Lake Quality
North Dakota, 3 lakes, average grade B (Good)
Only 3 lakes in McLean County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.
A meaningful share of McLean's lakes break 50 feet of depth, which matters because deep lakes hold cooler water all summer and resist the resuspended-sediment problems that plague shallow basins. The county's best-graded lake is Lake Audubon (B).
Quick Answers for McLean County
Planning a trip? Check special fishing regulations for Lake Audubon, whether the fish are safe to eat, and the best times to fish — or check the official North Dakota fishing regulations.
Fishing in McLean County
All Lakes in McLean County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Lake Audubon | B | 4.7 ft | 59.4 ft | - |
| 2 | Custer Mine Pond | C | 2.2 ft | 23.7 ft | - |
Other Counties in North Dakota
See how McLean County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 15 states.
Where to stay near McLean County
Top-rated places to stay near McLean County
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Source: EPA National Aquatic Resource Surveys, 2026.