Pony Express Lake
DeKalb County, Missouri164 acresView mapDirections
Missouri DNR publishes the water-quality measurements for Pony Express Lake. Here is what has been measured.
- Eutrophic
- Impaired · Algal growth
- 31 ft max depth
- Public access
- Limited data
Pony Express Lake in DeKalb County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 53.2 µg/L. Chlorophyll-a (algae): 26.3 µg/L. Surface area: 164 acres.
Pony Express Lake is a 164-acre productive, nutrient-rich eutrophic lake in DeKalb County, Missouri with an estimated average depth of about 31 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 3 public boat landings. Compared to the 4 other monitored lakes in DeKalb County, Pony Express Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-08-07. Methodology: how these readings are compared.
What Pony Express Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch3 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. Pony Express Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
Whether Pony Express Lake is safe to swim in today is a call for the Missouri Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Pony Express Lake
These are the measurements Missouri DNR publishes for Pony Express Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.3 ft of visibility. Phosphorus 53.2 µg/L. Chlorophyll-a 26.3 µg/L. TSI 66.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 53.2µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 26.3µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 66 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Pony Express Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Pony Express Lake typically sits around 80°F at the surface in August. Summer average is about 80°F. Usually warmest in Jul (about 83°F) and coldest in May (about 69°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (69°F) to its warmest (83°F).
Typical surface water temperature by month, from 10 field readings (2016–2024) via the EPA Water Quality Portal. See the full Pony Express Lake water temperature breakdown →
Lake Details
Max depth
~31 ft est.
Surface area
164 acres
Public access
Yes
Listed by Missouri DNR
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Missouri has not published bathymetry for Pony Express Lake.
Lake Size & Watershed
Watershed (drainage) area
5 sq mi
HydroLAKES / HydroSHEDS
Shoreline
5.5 mi
HydroLAKES / HydroSHEDS
Elevation
974 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
- Pony Express Lake Conservation AreaPublic
- Pony Express Lake Conservation AreaPublic
- Pony Express Lake Conservation 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 Pony Express Lake
Compare lakeside cabins, hotels, and vacation rentals near Pony Express Lake in DeKalb County, Missouri — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Pony Express Lake are listed below.
Top-rated places to stay near Pony Express Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Planning a trip? Cabins and lodging at Pony Express Lake → · more Missouri lake trips
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Fishing Pony Express Lake
Water quality readings over time
3 seasons of samples on record (2021–2024). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Phosphorus
Worsening+3.54 µg/L/yr3 years
Chlorophyll-a
Improving-5.41 µg/L/yr3 years
Reservoir Info (USACE NID)
Pony Express Lake is a man-made reservoir impounded by the Pony Express Lake Dam (completed 1963), built primarily for recreation on the TR-WEST FORK LOST CREEK; earth-type dam, 40 ft tall and 1,600 ft long.
- Surface area
- 164 ac
- Normal storage
- 2,400 ac-ft
- Max storage
- 3,560 ac-ft
- Drainage area
- 4.14 sq mi
- Hazard class
- High
- Owner
- MO DEPT OF CONSERVATION
Source: USACE National Inventory of Dams, NID ID MO10171 · Operator website
EPA Impairment Status
Pony Express Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life.
Source: EPA ATTAINS assessment unit MO_7118.00 · Official waterbody report
Nearby Lakes in DeKalb County
Frequently asked questions about Pony Express Lake
Where is Pony Express Lake?
- Pony Express Lake is a lake in DeKalb County, Missouri. Its water-quality measurements are published by Missouri DNR and shown on this page as reported.
What is the water quality of Pony Express Lake?
- Pony Express Lake in DeKalb County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 53.2 µg/L. Chlorophyll-a (algae): 26.3 µg/L. Surface area: 164 acres.
Is Pony Express Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Pony Express Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
What is the water temperature of Pony Express Lake?
- Pony Express Lake typically sits around 80°F at the surface in August, from 10 EPA Water Quality Portal field readings (2016–2024). That is a typical value for the month, not a live reading.
How deep is Pony Express Lake?
- No published bathymetric survey covers Pony Express Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 31 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 164 acres.
Are there boat ramps on Pony Express Lake?
- Pony Express Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Pony Express Lake Conservation Area, Pony Express Lake Conservation Area, Pony Express Lake Conservation Area. Public access is listed as yes.
Can I fish at Pony Express Lake?
- Pony Express Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Missouri's fish and wildlife agency, so check its current regulations before you go.
Explore Pony Express Lake across LakeQuality
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Where this data comes from
11 measurements from 2 monitoring stations, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC8 samples · 2024 - Missouri Dept. of Natural Resources
MDNR3 samples · 2023
Analytical methods
- Depth, Secchi disk in meters
- Nitrogen and Phosphorus, Total, Whole-water, Alkaline Persulfate Digest
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory