Timothy Lake
Clackamas County, Oregon1,430 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Oligotrophic
- #1 of 1 in the county
- 76 ft max depth
- Public access
- Limited data
Timothy Lake in Clackamas County, Oregon has a water quality grade of A (Excellent). Chlorophyll-a (algae): 1.2 µg/L. Surface area: 1430 acres.
- Max depth
- ~76 ft est.
- Area
- 1,430 acres
- Type
- Oligotrophic
- Chlorophyll-a
- 1.2 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
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Timothy Lake is a 1,430-acre cold, clear oligotrophic lake in Clackamas County, Oregon with an estimated average depth of about 76 feet. Water quality is graded A based on 1 sampling years through 2025. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 4 public boat landings.
Source: EPA Water Quality Portal sampling records, Oregon DEQ, last sampled 2025-10-07. Grade methodology: LakeQuality methodology.
What Timothy Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch4 documented ramps
- Camping9 public campgrounds nearby
- Big water1,430 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. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
No clarity data. Chlorophyll-a 1.2 µg/L. TSI 32. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 1.2 µg/L | Good |
| Trophic State Index (TSI) | 32 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~76 ft est. |
| Average Depth | ~51 ft est. |
| Surface Area | 1,430 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Oregon has not published bathymetry for Timothy Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Hoodview CampgroundPublic
- Gone Creek CampgroundPublic
- Pine Point CampgroundPublic
- Oak Fork CampgroundPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Timothy Lake
- Pine Point Campground0.2 km
- The Cove Campground0.4 km
- Meditation Point Campground1.7 km
- Oak Fork Campground2.0 km
- Gone Creek Campground2.1 km
- Hoodview Campground2.1 km
- North Arm Campground4.4 km
- Joe Graham Horse Camp4.6 km
- Clackamas Lake Campground4.7 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 Timothy Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Chlorophyll-a | ↓ Declining | +1.6 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Timothy Lake is a man-made reservoir impounded by the Timothy Lake (completed 1956), built primarily for hydroelectric on the Oak Grove River; earth-type dam, 100 ft tall and 740 ft long.
- Surface area
- 1,430 ac
- Normal storage
- 66,000 ac-ft
- Max storage
- 69,000 ac-ft
- Drainage area
- 54 sq mi
- Hazard class
- High
- Owner
- Portland General Electric Company
All listed purposes: Hydroelectric;Recreation.
Source: USACE National Inventory of Dams, NID ID OR00545 · Operator website
County Ranking
Ranked #1 of 1 lakes in Clackamas County
Nearby Lakes in Clackamas County
Frequently asked questions about Timothy Lake
Where is Timothy Lake?
- Timothy Lake is a lake in Clackamas County, Oregon. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Timothy Lake?
- Timothy Lake in Clackamas County, Oregon has a water quality grade of A (Excellent). Chlorophyll-a (algae): 1.2 µg/L. Surface area: 1430 acres.
Is Timothy Lake safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Timothy Lake?
- No published bathymetric survey covers Timothy Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 76 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 1430 acres.
Are there boat ramps on Timothy Lake?
- Timothy Lake has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Hoodview Campground, Gone Creek Campground, Pine Point Campground, Oak Fork Campground. Public access is listed as yes.
Are there campgrounds on Timothy Lake?
- Timothy Lake has 9 public campgrounds from USGS The National Map within 5 km, including Pine Point Campground, The Cove Campground, Meditation Point Campground, Oak Fork Campground. 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 Timothy Lake across LakeQuality
3 documented falls within 22.1 mi, nearest Umbrella Falls
4 thermal springs within 21.9 mi, nearest Austin 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.
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Other Grade A Lakes in Oregon
Oligotrophic Lakes in Oregon
Where this data comes from
8 measurements from 1 monitoring station, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Department of Environmental Quality - State of Oregon
OREGONDEQ8 samples · 2024–2025
Analytical methods
- 10200 H ~ Chlorophyll a-b-c Determination
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles