Jackson Park Outer Harbor Lake is a productive, nutrient-rich eutrophic lake in Cook County, Illinois. Water quality is graded D based on 1 sampling years through 2023. Compared to the 67 other monitored lakes in Cook County, Jackson Park Outer Harbor Lake ranks #32 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois DNR, last sampled 2023-05-04. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 6 ft. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Jackson Park Outer Harbor Lake
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Fishing Jackson Park Outer Harbor Lake
Current Conditions
Latest reading Sep 4, 2018, 2:56 PM from USGS gauge 04092440. See live data ↗ — readings update every 15–60 minutes; this page refreshes on each build.
Water Temperature
Jackson Park Outer Harbor Lake averages about 69°F at the surface in summer, usually warmest in Jul (about 77°F) and coldest in Oct (about 58°F). These are typical values by month — see Current Conditions above for the latest gauge reading.
Typical surface water temperature by month, from 10 field readings (2015–2023) via the EPA Water Quality Portal. See the full Jackson Park Outer Harbor Lake water temperature breakdown →
Location
County Ranking
Ranked #32 of 68 lakes in Cook County
Nearby Lakes in Cook County
Explore Jackson Park Outer Harbor Lake across LakeGrade
More Illinois Lake Rankings
Other Grade D Lakes in Illinois
Eutrophic Lakes in Illinois
More records, surveys & data sources
EPA Impairment Status
Jackson Park Outer Harbor Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit IL_QZM · Official waterbody report · Matched by proximity (0.15 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Jackson Park Outer Harbor Lake under Clean Water Act (NPDES) discharge permits.
- City Of ChicagoChicago · 2.1 mi away · NPDES IL0002429
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-05-04
Monitoring stations: 1