Tongue River Reservoir
Tongue River Reservoir in Big Horn County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 2158 acres.
- Area
- 2,158 acres
- Public access
- Yes
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Why Tongue River 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 Tongue River 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 Montana DEQ and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Tongue River Reservoir is a 2,158-acre lake in Big Horn County, Montana. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Montana DEQ, last sampled recent years. Grade methodology: LakeQuality methodology.
Watch Tongue River 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 Tongue River 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 Tongue River Reservoir
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 2,158 acres |
| Public Access | Yes |
No bathymetric survey has been published for Tongue River Reservoir, so its depth is not documented here.
Recreation & Access
- Tongue River Reservoir State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Tongue River Reservoir
Nearby Lakes in Big Horn County
Frequently asked questions about Tongue River Reservoir
Where is Tongue River Reservoir?
- Tongue River Reservoir is a lake in Big Horn County, Montana. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Tongue River Reservoir?
- Tongue River Reservoir in Big Horn County, Montana is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 2158 acres.
Is Tongue River Reservoir safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Tongue River 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 Tongue River Reservoir?
- Tongue River Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Tongue River Reservoir State Park. Public access is listed as yes.
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Where this data comes from
Measurements for Tongue River Reservoir come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory