Boyd Lake
Larimer County, Colorado1,747 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
↑ up from D at the last regrade
- Mesotrophic
- #2 of 9 in the county
- Public access
- Limited data
Boyd Lake in Larimer County, Colorado has a water quality grade of A (Excellent). Water clarity: 4.6 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.1 µg/L. Surface area: 1747 acres.
- Clarity
- 4.6 ft
- Area
- 1,747 acres
- Type
- Mesotrophic
- Public access
- Yes
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Watch Boyd Lake’s letter
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Boyd Lake is a 1,747-acre mesotrophic lake in Larimer County, Colorado. Water quality is graded A based on 3 sampling years through 2021. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 8 other monitored lakes in Larimer County, Boyd Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2021-09-08. Grade methodology: LakeQuality methodology.
What Boyd Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
- Big water1,747 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)
Murky, only visible to about 4.6 ft. Phosphorus 20 µg/L. Chlorophyll-a 5.1 µg/L. TSI 50. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.6 ft | Not graded |
| Phosphorus | 20 µg/L | Good |
| Chlorophyll-a (Algae) | 5.1 µg/L | Good |
| Trophic State Index (TSI) | 50 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1,747 acres |
| Public Access | Yes |
No bathymetric survey has been published for Boyd Lake, so its depth is not documented here.
Recreation & Access
- Boyd Lake State ParkPublic
- Boyd Lake State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Boyd Lake
Reservoir Info (USACE NID)
Boyd Lake is a man-made reservoir impounded by the Boyd Lake (completed 1900), built primarily for fish and wildlife pond on the Big Thompson River-Os; earth-type dam, 40 ft tall and 10,729 ft long.
- Surface area
- 1,747 ac
- Normal storage
- 48,871 ac-ft
- Max storage
- 59,981 ac-ft
- Drainage area
- 17 sq mi
- Hazard class
- High
- Owner
- GREELEY-LOVELAND IRRIGATION COMPANY (DAN KAMMERZEL
All listed purposes: Fish and Wildlife Pond;Irrigation;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID CO00157 · Operator website
County Ranking
Ranked #2 of 9 lakes in Larimer County
Nearby Lakes in Larimer County
Frequently asked questions about Boyd Lake
Where is Boyd Lake?
- Boyd Lake is a lake in Larimer County, Colorado. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Boyd Lake?
- Boyd Lake in Larimer County, Colorado has a water quality grade of A (Excellent). Water clarity: 4.6 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.1 µg/L. Surface area: 1747 acres.
Is Boyd Lake safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Boyd Lake?
- Boyd Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Boyd Lake State Park, Boyd Lake State Park. Public access is listed as yes.
Explore Boyd Lake across LakeQuality
12.2 mi away · cable-pulled, no boat wake
Species activity outlook by water temperature and season
Where to stay at Colorado's top lakes, each with its grade
Moderate nutrients, good water quality
Colorado's cleanest and most-polluted lakes, ranked
Planning a trip around Rocky Mountain?
Boyd Lake is about 35 miles from Rocky Mountain 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 Rocky Mountain →More Colorado Lake Rankings
Other Grade A Lakes in Colorado
Mesotrophic Lakes in Colorado
Where this data comes from
12 measurements from 1 monitoring station, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX12 samples · 2021
Analytical methods
- Secchi disk depth measurement
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Nitrogen in Water by Pyrolysis Detection
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
Named boat-access points from the USGS National Boat Ramps inventory