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LakeQuality

Four Lake vs Isabella Lake

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

Four Lake and Isabella Lake both received the same overall water quality grade of C (Fair). Both are in Lake County, Minnesota.

Reviewed by LakeQuality Editorial Team · Updated

Four Lake and Isabella Lake are both in Minnesota — 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. These two are within a letter of each other on the rubric — Four Lake (C) versus Isabella Lake (C). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.

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.

C

Four Lake

Lake County, Minnesota

Moderate clarity, visible to about 8 ft.

C

Isabella Lake

Lake County, Minnesota

Murky, only visible to about 4.4 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.

MetricFour LakeIsabella Lake
Overall GradeC (Fair)C (Fair)
Water Clarity8 ft4.4 ft
PhosphorusNo data20 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth25 ft19 ft
Surface Area610.88 acres1.3K acres
Public AccessNoYes
Fish Species911
Trophic Statemesotrophiceutrophic

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

Verdict

Both lakes earn the same Grade C. The tiebreakers come down to clarity (Four Lake: 8 ft, Isabella Lake: 4.4 ft) and what you want from the lake. Four Lake has fewer fish species than Isabella Lake.