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B

Morton Lake

Vilas County, WisconsinLimited DataMesotrophic

Morton Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. Morton Lake reaches 29 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. Morton Lake covers 165 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Morton Lake sits at rank 121 of 191 in Vilas County, in the lower half of the local distribution.

Morton Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. Walleye are documented at Morton Lake, one of 5 fish species on record for the lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-24. Grade methodology: LakeGrade methodology.

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Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Good clarity, visible to about 10.5 ft. Trophic State Index: 43.

MetricValueGrade
Water Clarity (Secchi Depth)10.5 ftB
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)43Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth29 ft
Surface Area165 acres

Fish Species

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

→ Best fishing times for Morton Lake (14-day solunar calendar)

→ Is it safe to eat fish from Morton Lake? (mercury & PFAS guide)

Morton Lake fishing regulations (limits, seasons, special rules)

Water Quality Trend: Improving

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.75 m/yr5
Phosphorus Improving-5.5 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #121 of 191 lakes in Vilas County

Cleaner Lakes Within 30 Miles

Morton Lake holds Grade B. One nearby lake has a higher grade.

Nearby Lakes in Vilas County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1990. 1 station on file (most recent sample 2025).

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Common)Musky(Present)Northern Pike(Present)Walleye(Present)

EPA Impairment Status

Morton Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Cause unknown

Source: EPA ATTAINS assessment unit WI10007538 · Official waterbody report · Matched by proximity (2.03 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Fish and recreation data from Wisconsin DNR Lakes

Most recent sample: 2025-08-24

Monitoring stations: 1

Where to stay near Morton Lake

Compare lakeside cabins, hotels, and vacation rentals near Morton Lake in Vilas County, Wisconsin — live availability and prices for your trip.

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