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LakeQuality

Iron Lake vs Nibin Lake

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

Iron Lake and Nibin Lake both received the same overall water quality grade of D (Poor). Both are in St. Louis County, Minnesota.

Reviewed by LakeQuality Editorial Team · Updated

Both Iron Lake and Nibin Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. The grades are close: Iron Lake (D) and Nibin Lake (D) 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.

D

Iron Lake

St. Louis County, Minnesota

Murky, only visible to about 5 ft.

D

Nibin Lake

St. Louis County, Minnesota

Murky, only visible to about 5.6 ft.

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.

MetricIron LakeNibin Lake
Overall GradeD (Poor)D (Poor)
Water Clarity5 ft5.6 ft
PhosphorusNo dataNo data
Chlorophyll-a (Algae)No dataNo data
Maximum Depth64 ft40 ft
Surface Area2.0K acres775.93 acres
Public AccessNoNo
Fish Species95
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 D. The tiebreakers come down to clarity (Iron Lake: 5 ft, Nibin Lake: 5.6 ft) and what you want from the lake. Iron Lake supports more documented fish species.