Long Lake vs Willmar Lake
Water quality, depth, fish species, and recreation comparison.
Willmar Lake has a higher water quality grade (D, Poor) than Long Lake (F, Very Poor). Both are in Kandiyohi County, Minnesota.
Both Long Lake and Willmar 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: Long Lake (F) and Willmar 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.
Long Lake
Murky, only visible to about 5 ft.
Willmar Lake
Very murky, less than 2 ft of visibility.
Side-by-Side Metrics
| Metric | Long Lake | Willmar Lake |
|---|---|---|
| Overall Grade | F (Very Poor) | D (Poor) |
| Water Clarity | 5 ft | 2 ft |
| Phosphorus | 92 µg/L | 73 µg/L |
| Chlorophyll-a (Algae) | 42.3 µg/L | 27.6 µg/L |
| Maximum Depth | 16 ft | 14 ft |
| Surface Area | 1,573 acres | 636 acres |
| Public Access | Yes | Yes |
| Fish Species | 16 | 18 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Willmar Lake wins on overall water quality with a Grade D versus Long Lake's Grade F. Water clarity: 2 ft vs 5 ft. For fishing diversity, Willmar Lake also leads with 18 species.
Source: EPA National Aquatic Resource Surveys, 2026.