Posey Lake
Garfield County, Utah11 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Oligotrophic
- #3 of 10 in the county
- Public access
- Limited data
Posey Lake in Garfield County, Utah has a water quality grade of A (Excellent). Water clarity: 16.4 ft visibility. Phosphorus: 18.5 µg/L. Chlorophyll-a (algae): 1.2 µg/L. Surface area: 11 acres.
- Clarity
- 16.4 ft
- Area
- 11 acres
- Type
- Oligotrophic
- Phosphorus
- 18.5 µg/L
- Chlorophyll-a
- 1.2 µg/L
- Trend
- ↑ Improving
- Public access
- Yes
Stays via Stay22
Stays near Posey Lake
Compare lakeside cabins, hotels, and vacation rentals near Posey Lake in Garfield County, Utah — 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 Posey Lake
Prices for Sep 11–13, 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.
Planning a whole trip? See where to stay at Utah’s top lakes →
Watch Posey Lake’s letter
Email me if this lake’s grade moves. Grades stay free.
Or email
Posey Lake is a 11-acre cold, clear oligotrophic lake in Garfield County, Utah. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 9 other monitored lakes in Garfield County, Posey Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Utah DWQ, last sampled 2025-09-03. Grade methodology: LakeQuality methodology.
What Posey Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.4 ft of visibility
- Camping1 public campground nearby
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)
Crystal clear, you can see 16.4 ft down. Phosphorus 18.5 µg/L. Chlorophyll-a 1.2 µg/L. TSI 39. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.4 ft | Not graded |
| Phosphorus | 18.5 µg/L | Good |
| Chlorophyll-a (Algae) | 1.2 µg/L | Good |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 11 acres |
| Public Access | Yes |
No bathymetric survey has been published for Posey Lake, so its depth is not documented here.
Recreation & Access
Public campgrounds near Posey Lake
- Posey Lake Campground0.3 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 Posey Lake
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.05 m/yr | 2 |
| Chlorophyll-a | ↑ Improving | -0.58 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Posey Lake is a man-made reservoir impounded by the Posy Lake, built primarily for recreation; earth-type dam, 15 ft tall and 120 ft long.
- Surface area
- 11 ac
- Normal storage
- 50 ac-ft
- Hazard class
- Low
- Owner
- USDA FS
All listed purposes: Recreation;Other.
Source: USACE National Inventory of Dams, NID ID UT00766 · Operator website
County Ranking
Ranked #3 of 10 lakes in Garfield County
Nearby Lakes in Garfield County
Frequently asked questions about Posey Lake
Where is Posey Lake?
- Posey Lake is a lake in Garfield County, Utah. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Posey Lake?
- Posey Lake in Garfield County, Utah has a water quality grade of A (Excellent). Water clarity: 16.4 ft visibility. Phosphorus: 18.5 µg/L. Chlorophyll-a (algae): 1.2 µg/L. Surface area: 11 acres.
Is Posey Lake safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Are there campgrounds on Posey Lake?
- Posey Lake has 1 public campground from USGS The National Map within 5 km, including Posey Lake 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 Posey Lake across LakeQuality
2 documented falls within 16.8 mi, nearest Upper Calf Creek Falls
Species activity outlook by water temperature and season
Where to stay at Utah's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
Utah's cleanest and most-polluted lakes, ranked
Planning a trip around Capitol Reef?
Posey Lake is about 34 miles from Capitol Reef 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 Capitol Reef →More Utah Lake Rankings
Other Grade A Lakes in Utah
Oligotrophic Lakes in Utah
Where this data comes from
16 measurements from 1 monitoring station, 2019–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Utah Department Of Environmental Quality
UTAHDWQ_WQX16 samples · 2019–2025
Analytical methods
- Field Measurements
- Phosphorus by Colorimetry
- 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
Public campgrounds from USGS The National Map Structures, within about 3 miles