Ransom County Lake Quality
North Dakota, 3 lakes — no lake here has enough monitoring data for a grade
Ransom County has 3 monitored 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. No lake in Ransom County has enough sampling behind it for an A–F grade yet. The 3 monitored lakes below carry whatever clarity, phosphorus, and chlorophyll-a measurements exist.
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.
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Quick Answers for Ransom County
Planning a trip? Check special fishing regulations for Dead Colt Creek Dam Lake — or check the official North Dakota fishing regulations.
All Lakes in Ransom County
3 lakes · 0 graded, 3 not rated0 graded lakes · 3 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| NRDead Colt Creek Dam LakeRansom | NR | 3.3 ft | No recent samples | 32.3 µg/L | No recent samples | ✓ Public | |
| NRLone Tree LakeRansom | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBrowen LakeRansom | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
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Other Counties in North Dakota
See how Ransom County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..
Source: EPA National Aquatic Resource Surveys, 2026.