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LakeQuality

Lake Butte des Morts vs Lake Poygan

Water quality, depth, fish species, and recreation comparison.

Lake Butte des Morts and Lake Poygan both received the same overall water quality grade of F (Very Poor). Both are in Winnebago County, Wisconsin.

Lake Butte des Morts and Lake Poygan are both in Wisconsin — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The grades are close: Lake Butte des Morts (F) and Lake Poygan (F) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.

With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.

F

Lake Butte des Morts

Winnebago County, Wisconsin

Very murky, less than 2.3 ft of visibility.

F

Lake Poygan

Winnebago County, Wisconsin

Very murky, less than 2.5 ft of visibility.

Side-by-Side Metrics

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

MetricLake Butte des MortsLake Poygan
Overall GradeF (Very Poor)F (Very Poor)
Water Clarity2.3 ft2.5 ft
PhosphorusNo dataNo data
Chlorophyll-a (Algae)No dataNo data
Maximum Depth9 ft11 ft
Surface Area8.6K acres14.0K acres
Public AccessUnknownUnknown
Fish Species00
Trophic Stateeutrophiceutrophic

Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).

Verdict

Both lakes earn the same Grade F. The tiebreakers come down to clarity (Lake Butte des Morts: 2.3 ft, Lake Poygan: 2.5 ft) and what you want from the lake. Lake Butte des Morts matches its peer on species count.