Marshall County Lake Quality
Indiana, 3 lakes, average grade C (Fair)
Marshall County has 3 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Lost Lake (D) is the cleanest in the county.
Quick Answers for Marshall County
Planning a trip? Check special fishing regulations for Lost Lake, whether the fish are safe to eat, and the best times to fish — or check the official Indiana fishing regulations.
All Lakes in Marshall County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Lost Lake | D | 4.9 ft | - |
Other Counties in Indiana
See how Marshall 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 Marshall County
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Source: EPA National Aquatic Resource Surveys, 2026.