Lon Hagler Reservoir
Larimer County, Colorado201 acresView mapDirections
Colorado WQCD publishes the water-quality measurements for Lon Hagler Reservoir. Here is what has been measured.
- Mesotrophic
- 16 ft max depth
- Public access
- Limited data
Lon Hagler Reservoir in Larimer County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 4.6 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 3.8 µg/L. Surface area: 201 acres.
Lon Hagler Reservoir is a 201-acre mesotrophic lake in Larimer County, Colorado with an estimated average depth of about 16 feet. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 8 other monitored lakes in Larimer County, Lon Hagler Reservoir ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2021-09-09. Methodology: how these readings are compared.
Lon Hagler Reservoir covers about 200 acres in Larimer County. It has 2 public boat landings, so a lakefront rental is not the only way to get a boat on the water. If you are planning to stay, you can search lake houses and cabins around Lon Hagler Reservoir on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Lon Hagler Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lon Hagler Reservoir is safe to swim in today is a call for the Water Quality Control Division of the Colorado Department of Public Health and Environment and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lon Hagler Reservoir
These are the measurements Colorado WQCD publishes for Lon Hagler Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4.6 ft. Phosphorus 20 µg/L. Chlorophyll-a 3.8 µg/L. TSI 49.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 20µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 3.8µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Lon Hagler Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~16 ft est.
Surface area
201 acres
Public access
Yes
Listed by Colorado WQCD
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Lon Hagler Reservoir.
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.2 mi
HydroLAKES / HydroSHEDS
Elevation
5,154 ft
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
- Lon Hagler State Wildlife AreaPublic
- Lon Hagler State Wildlife AreaPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Lon Hagler Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Lon Hagler Reservoir in Larimer County, Colorado — 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 Lon Hagler Reservoir
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
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Fishing Lon Hagler Reservoir
Reservoir Info (USACE NID)
Lon Hagler Reservoir is a man-made reservoir impounded by the Lon Hagler (completed 1967), built primarily for irrigation on the Big Thompson River-Os; earth-type dam, 71 ft tall and 5,085 ft long.
- Surface area
- 201 ac
- Normal storage
- 5,228 ac-ft
- Max storage
- 6,275 ac-ft
- Drainage area
- 0 sq mi
- Hazard class
- High
- Owner
- CONSOLIDATED HOME SUPPLY DITCH & RES. CO (DAVE SCH
All listed purposes: Irrigation;Recreation.
Source: USACE National Inventory of Dams, NID ID CO00165 · Operator website
Nearby Lakes in Larimer County
Frequently asked questions about Lon Hagler Reservoir
Where is Lon Hagler Reservoir?
- Lon Hagler Reservoir is a lake in Larimer County, Colorado. Its water-quality measurements are published by Colorado WQCD and shown on this page as reported.
What is the water quality of Lon Hagler Reservoir?
- Lon Hagler Reservoir in Larimer County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 4.6 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 3.8 µg/L. Surface area: 201 acres.
Is Lon Hagler Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lon Hagler Reservoir?
- No published bathymetric survey covers Lon Hagler Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 16 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 201 acres.
Are there boat ramps on Lon Hagler Reservoir?
- Lon Hagler Reservoir has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lon Hagler State Wildlife Area, Lon Hagler State Wildlife Area. Public access is listed as yes.
Can I fish at Lon Hagler Reservoir?
- Lon Hagler Reservoir has 2 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Colorado's fish and wildlife agency, so check its current regulations before you go.
Explore Lon Hagler Reservoir across LakeQuality
Planning a trip around Rocky Mountain?
Lon Hagler Reservoir is about 29 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 lakes in Colorado
Other Lakes in Colorado
Mesotrophic Lakes in Colorado
Where this data comes from
18 measurements from 2 monitoring stations, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX18 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 (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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