Crescent Lake
Klamath County, Oregon4,008 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Oligotrophic
- Impaired · Oxygen depletion (low DO)
- #1 of 17 in the county
- Public access
- Limited data
Crescent Lake in Klamath County, Oregon has a water quality grade of A (Excellent). Water clarity: 42.2 ft visibility. Chlorophyll-a (algae): 1.2 µg/L. Surface area: 4008 acres.
- Clarity
- 42.2 ft
- Area
- 4,008 acres
- Type
- Oligotrophic
- Chlorophyll-a
- 1.2 µg/L
- Trend
- ↑ Improving
- Public access
- Yes
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Watch Crescent Lake’s letter
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Crescent Lake is a 4,008-acre cold, clear oligotrophic lake in Klamath County, Oregon. Water quality is graded A based on 1 sampling years through 2021. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 16 other monitored lakes in Klamath County, Crescent Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Oregon DEQ, last sampled 2021-08-19. Grade methodology: LakeQuality methodology.
What Crescent Lake is good for
From access and monitoring records, not editorial picks.
- Clear water42.2 ft of visibility
- Boat launch1 documented ramp
- Camping3 public campgrounds nearby
- Big water4,008 acres
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The A is nutrients and algae, not a swimming clearance. Crescent Lake is listed impaired under Clean Water Act §303(d) (IR 5) for oxygen depletion (low DO). Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Crystal clear, you can see 42.2 ft down. Chlorophyll-a 1.2 µg/L. TSI 28. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 42.2 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 1.2 µg/L | Good |
| Trophic State Index (TSI) | 28 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 4,008 acres |
| Public Access | Yes |
No bathymetric survey has been published for Crescent Lake, so its depth is not documented here.
Recreation & Access
- Spring CampgroundPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Crescent Lake
- Spring2.8 km
- Whitefish Horse Camp3.4 km
- Windy Group Site3.6 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Fishing Crescent Lake
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.967 m/yr | 2 |
| Chlorophyll-a | ↑ Improving | -0.2 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Crescent Lake is a man-made reservoir impounded by the Crescent Lake (completed 1956), built primarily for irrigation on the Crecent Lake; earth-type dam, 41 ft tall and 1,250 ft long.
- Surface area
- 4,008 ac
- Normal storage
- 86,050 ac-ft
- Max storage
- 119,600 ac-ft
- Drainage area
- 61 sq mi
- Hazard class
- High
- Owner
- TUMALO IRRIGATION DISTRICT
All listed purposes: Irrigation;Recreation.
Source: USACE National Inventory of Dams, NID ID OR00381 · Operator website
EPA Impairment Status
Crescent Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit OR_LK_1707030202_05_100084 · Official waterbody report
County Ranking
Ranked #1 of 17 lakes in Klamath County
Nearby Lakes in Klamath County
Frequently asked questions about Crescent Lake
Where is Crescent Lake?
- Crescent Lake is a lake in Klamath County, Oregon. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Crescent Lake?
- Crescent Lake in Klamath County, Oregon has a water quality grade of A (Excellent). Water clarity: 42.2 ft visibility. Chlorophyll-a (algae): 1.2 µg/L. Surface area: 4008 acres.
Is Crescent Lake safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Crescent Lake is listed impaired under Clean Water Act §303(d) (IR 5) for oxygen depletion (low DO). Check local advisories before you swim.
Are there boat ramps on Crescent Lake?
- Crescent Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Spring Campground. Public access is listed as yes.
Are there campgrounds on Crescent Lake?
- Crescent Lake has 3 public campgrounds from USGS The National Map within 5 km, including Spring, Whitefish Horse Camp, Windy Group Site. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Crescent Lake across LakeQuality
2 documented falls within 19.9 mi, nearest Lemolo Falls
2 thermal springs within 23.9 mi, nearest Umpqua Hot Springs
Species activity outlook by water temperature and season
Where to stay at Oregon's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
Oregon's cleanest and most-polluted lakes, ranked
Planning a trip around Crater Lake?
Crescent Lake is about 38 miles from Crater Lake National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Crater Lake →More Oregon Lake Rankings
Other Grade A Lakes in Oregon
Oligotrophic Lakes in Oregon
Where this data comes from
10 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Department of Environmental Quality - State of Oregon
OREGONDEQ10 samples · 2021
Analytical methods
- 2012 National Lakes Assessment Field Operations Manual
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles