Boulder Lake Reservoir
Boulder Lake Reservoir in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 3287 acres.
- Area
- 3,287 acres
- Public access
- Yes
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Why Boulder Lake Reservoir has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Boulder Lake Reservoir, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Boulder Lake Reservoir is a 3,287-acre lake in St. Louis County, Minnesota. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled recent years. Grade methodology: LakeQuality methodology.
Watch Boulder Lake Reservoir water quality
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Boulder Lake Reservoir
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near Boulder Lake Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Boulder Lake Reservoir in St. Louis County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Boulder Lake Reservoir
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 3,287 acres |
| Public Access | Yes |
No bathymetric survey has been published for Boulder Lake Reservoir, so its depth is not documented here.
Recreation & Access
- Boulder LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Boulder Lake Reservoir
Nearby Lakes in St. Louis County
Frequently asked questions about Boulder Lake Reservoir
Where is Boulder Lake Reservoir?
- Boulder Lake Reservoir is a lake in St. Louis County, Minnesota. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Boulder Lake Reservoir?
- Boulder Lake Reservoir in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 3287 acres.
Is Boulder Lake Reservoir safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Boulder Lake Reservoir is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Are there boat ramps on Boulder Lake Reservoir?
- Boulder Lake Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Boulder Lake. Public access is listed as yes.
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Where this data comes from
Measurements for Boulder Lake Reservoir come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory