
Hill County Lake Quality
Montana, 25 lakes — no lake here has enough monitoring data for a grade
There are 25 monitored lakes in Hill County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. No lake in Hill County has enough sampling behind it for an A–F grade yet. The 25 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 Hill County
Planning a trip? Check special fishing regulations for McKinnsey Reservoir — or check the official Montana fishing regulations.
All Lakes in Hill County
25 lakes · 0 graded, 25 not rated0 graded lakes · 25 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| NRMcKinnsey ReservoirHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBurkhartsmeyer ReservoirHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRHingham LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLower LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBearpaw LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBailey ReservoirHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRSage LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRDry LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRChain of LakesHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRChain of LakesHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRFresno ReservoirHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRSands LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRHalfway LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMartin LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRDry LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRGrassy LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake ThibadeauHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRDiversionHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMud LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMud LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMud LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMud LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMud LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRGrassy LakeHill | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRGrassy LakeHill | 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
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Other Counties in Montana
See how Hill 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.