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LakeQuality

Emily Lake

F
Grade F — Algae-prone
Algae-prone · #9 of 13 lakes in the county · 2 ft clear · Eutrophic · 300 acres · from D
Eutrophic

Emily Lake in Le Sueur County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2 ft visibility. Phosphorus: 61 µg/L. Chlorophyll-a (algae): 42.7 µg/L. Maximum depth: 37 ft. Surface area: 300 acres.

Clarity
2 ft
Typical in August
77°F
Max depth
37 ft
Area
300 acres
Type
Eutrophic
Trend
Improving
Public access
Yes
Ice-out
Mar 30
Open water
246 days

Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Emily Lake

Next lake in Le Sueur County

FWashington Lake4.5 ft clear · Le Sueur CountyView →
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Emily Lake is a 300-acre productive, nutrient-rich eutrophic lake in Le Sueur County, Minnesota with a maximum depth of 37 feet. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 14 documented fish species including bigmouth buffalo, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 12 other monitored lakes in Le Sueur County, Emily Lake ranks #9 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-26. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Algae risk

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.

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom

Compare the safest swimming lakes near Mankato

Get alerts for Emily Lake

Water Quality Grade: F (Algae-prone)

Very murky, less than 2 ft of visibility. Phosphorus level: 61 µg/L. Chlorophyll-a: 42.7 µg/L. Trophic State Index: 66.

MetricValueGrade
Water Clarity (Secchi Depth)2 ftNot graded
Phosphorus61 µg/LPoor
Chlorophyll-a (Algae)42.7 µg/LPoor
Trophic State Index (TSI)66Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Emily Lake

Compare lakeside cabins, hotels, and vacation rentals near Emily Lake in Le Sueur County, Minnesota — 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 grade measures nutrients and algae, not lodging — cabins and rentals around Emily Lake are listed below.

Top-rated places to stay near Emily Lake

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 Minnesota’s top lakes →

Water Temperature

Emily Lake typically sits around 77°F at the surface in August. Summer average is about 77°F. Usually warmest in Jul (about 80°F) and coldest in Oct (about 65°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
67°
Jun
75°
Jul
80°
Aug
77°
Sep
72°
Oct
65°
Nov
Dec

Typical surface water temperature by month, from 66 field readings (20242025) via the EPA Water Quality Portal. See the full Emily Lake water temperature breakdown →

Blue-Green Algae (Cyanobacteria)

No current satellite reading

There’s no recent EPA CyAN cyanobacteria estimate for Emily Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (409,261 cells/mL) on July 18, 2026.

Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗

Lake Details

CharacteristicValue
Maximum Depth37 ft
Surface Area300 acres
Shoreline Length6.5 mi
Littoral Zone55%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
79 sq mi
Elevation
965 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Emily LakePublic

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Emily Lake

DNR Fisheries Survey Summary

15 surveys on file from MN DNR Fisheries. Most recent: 2024-07-11 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Crappie46.800.14 lb
Bluegill41.820.12 lb
Largemouth Bass11.081.48 lb
Yellow Perch8.590.1 lb
Bigmouth Buffalo3.693.93 lb
Black Bullhead3.260.83 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

Length Distributions

Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.

Black Crappie

186 fish · 39 in · 2024-07-11
111560trophy 103456789

Bluegill

976 fish · 26 in · 2024-07-11
687344023456

Largemouth Bass

1 fish · 1616 in · 2024-07-11
1016

Yellow Perch

6 fish · 45 in · 2024-07-11
32045

From the 2024-07-11 survey

A targeted survey of nearshore fish species in Emily Lake was conducted on July 15th 2024, by Index of Biological Integrity (IBI) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Emily Lake. 3 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 4 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.035 m/yr4
Phosphorus Improving-10 µg/L/yr2
Chlorophyll-a Declining+8 µg/L/yr2
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (16 observations).

Typical Ice-Out
Mar 30
Typical Ice-In
Dec 1

Estimated open water season: 246 days

EarliestLatest
Ice-Out2024-03-01 (2024)2018-04-29 (2018)
Ice-In2014-11-16 (2014)2015-12-19 (2015)

Most recent ice-out: 2025-03-15

Reservoir Info (USACE NID)

Emily Lake is a man-made reservoir impounded by the Lake Emily (completed 1939), built primarily for recreation on the Shanaska Creek-TR; concrete-type dam, 9 ft tall.

Surface area
315 ac
Normal storage
1,000 ac-ft
Max storage
3,000 ac-ft
Drainage area
1.7 sq mi
Hazard class
Low
Owner
MNDNR

Source: USACE National Inventory of Dams, NID ID MN01161 · Operator website

County Ranking

Ranked #9 of 13 lakes in Le Sueur County

Nearby Lakes With Higher Grades

Emily Lake holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.

See full comparison →

Nearby Lakes in Le Sueur County

Frequently asked questions about Emily Lake

What is the water quality grade for Emily Lake?

Emily Lake in Le Sueur County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2 ft visibility. Phosphorus: 61 µg/L. Chlorophyll-a (algae): 42.7 µg/L. Maximum depth: 37 ft. Surface area: 300 acres.

Is Emily Lake safe to swim in?

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Emily Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 42.7 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Emily Lake?

Emily Lake typically sits around 77°F at the surface in August, from 66 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.

How deep is Emily Lake?

Emily Lake has a maximum depth of 37 feet. The lake covers 300 acres.

What fish are in Emily Lake?

Fish species found in Emily Lake include bigmouth buffalo, black crappie, bluegill, channel catfish, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, walleye, white crappie, white sucker, yellow bullhead, yellow perch. Emily Lake is located in Le Sueur County, Minnesota.

When does Emily Lake thaw?

Emily Lake typically has ice-out around Mar 30. Ice typically forms around Dec 1. The open water season is approximately 246 days.

Does Emily Lake have blue-green algae?

There is no recent EPA CyAN cyanobacteria estimate for Emily Lake (clouds, ice, or an off-season gap). The most recent reading was high (409,261 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.

Are there boat ramps on Emily Lake?

Emily Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Emily Lake. Public access is listed as yes.

Where this data comes from

145 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA145 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Colorimetry
  • 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)

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)

Lake details from Minnesota DNR LakeFinder

Named boat-access points from the USGS National Boat Ramps inventory

Ice data from Minnesota DNR Climate