Sullivan Lake

Washtenaw County, Michigan · MI DNR bathymetric survey

22ft Max
depth

20 acres 5 contours Public access 20% weedy

Paddling Index86Very Goodsheltered geometry · wooded shoreline · away from major roads

Get directions

Depth scale

0510152022

The lake

Survey readout

Sullivan Lake is mapped to a depth of 22 ft on the Michigan DNR survey and covers about 20 acres in Washtenaw County, Michigan.

Measured from the Michigan DNR inland-lake contour survey.

Deepest sounding: 22 ft
Mean depth: 12.1 ft · estimated
Surface area: 20 acres
Estimated volume: 248 acre-ft · 81M gal
Shoreline: 0.9 mi · lobed
Aquatic vegetation: 20% of surface · NDVI estimate
Trophic state: Mesotrophic · measured 2007 · details
Public access: Boat Launch · Rec Passport
In: Pinckney Recreation Area · Michigan DNR

Additional depth details5 contours

Contour depths: 0–22 ft
Recorded point soundings: 22 ft

36.1% of the surface sits over water shallower than 10 ft; 11.9% is deeper than 20 ft. Depth, area and volume are estimated from the interpolated survey surface — historical reference, not measurement.

Compare with another lake

Location

Washtenaw County, Michigan · 15 nearest of 47 lakes · tap a dot for that lake

Chart data

Provenance

Sources: MI DNR inland lake contours, USGS 3DEP, USDA NAIP (public domain), OpenStreetMap (ODbL), MI DNR Boat Launches.

⚠ Not for navigation

Spot an error? Send a correction

Map details & sources5 sources

All layers registered to one bounding box; positions in WGS 84.

Survey-derived depth contours drape over USGS 3DEP elevation, with a USDA NAIP aerial basemap and OpenStreetMap shoreline. Color shows surveyed depth; dark lines are the survey's own isobaths.

Coordinates: 42.39854, -84.05692
MI DNR lake ID: L10159
Vertical exaggeration: 2.93× below the waterline; land at true scale
Basemap: USDA NAIP · public domain
Model size: 1.4 MB

Lake productivity & trophic state

Measured 2007

Classification: Mesotrophic. Moderate nutrient levels and biological productivity. Based on measurements recorded in 2007 (chlorophyll-a 2.7 µg/L).

Trophic state describes how biologically productive a lake is, based on indicators such as nutrients, algae and water clarity. It is not a swimming-safety or overall water-quality rating.

What do the categories mean?

Oligotrophic≤ 2 µg/L · lower nutrient and algae levels, often clearer water and lower biological productivity.
Mesotrophic · this lake2–7 µg/L · moderate nutrient levels and biological productivity.
Eutrophic7–30 µg/L · higher nutrient levels and biological productivity, often with more algae or aquatic plant growth.
Hypereutrophic> 30 µg/L · very high nutrient levels and biological productivity, with a greater potential for heavy algae growth and low water clarity.

Bands are summer (June–August) mean chlorophyll-a, the green pigment in algae, at the EPA 2012 National Lakes Assessment thresholds. Trophic condition can change over time and by measurement method. Source: Midwest Glacial Lakes Partnership Conservation Planner; chlorophyll-a measurements from LAGOS-US LIMNO.

Paddling

Paddling Index methodology v1.0 · calculated 2026-09-23

86 / 100Very GoodData confidence: High

Sullivan Lake has a heavily wooded and largely undeveloped setting, well sheltered geometry, limited nearby major-road exposure. No special watercraft restriction is identified in the current source.

Why this score?5 components

Included in the index

Component	Rating	Points of weight	Measurement
Natural setting	Excellent	27.5 of 30	87% natural land cover within 150 m of shore (25% forest, 62% wetland; 5% developed)
Geometric wind exposure	Excellent	25.0 of 25	mean fetch 365 m · 94% of sampled water within 500 m of shelter · short fetch in most directions
Watercraft controls	None identified	7.5 of 15	No special watercraft restriction identified in the current DNR source. Motors permitted, subject to general law.
Public access	Excellent	15.0 of 15	1 site with DNR boating-facility records · carry-in launch
Road isolation	Very Good	11.2 of 15	limited nearby major-road exposure · 4 MDOT-classified segments within 1.2 km, peak 2,716 vehicles/day

Additional paddling considerations

These describe the lake but are not part of the v1 Paddling Index and do not change the number above.

Wake sensitivity: Moderate — narrow in places — wakes would carry across parts of the lake
Aquatic vegetation: Moderate — approximately 20% mapped coverage · NAIP aerial imagery (NDVI)
Observed motorized activity: Unknown — No lake-level measurement of boat traffic is available. Legal permission to operate motors is not evidence of use.
Wildlife habitat potential: High — 25% forest and 62% wetland cover within 150 m of shore

Compare Michigan lakes by Paddling Index →

How this index is calculated. The Paddling Index is a relative composite derived from lake geometry and public environmental, access, roadway and watercraft-control data. It is not a user review, a safety rating, or a prediction of an individual outing. Differences of a few points should not be treated as meaningful — an 84 and an 82 are broadly comparable. Components and weights: natural setting 30%, geometric wind exposure 25%, watercraft controls 15%, public access 15%, road isolation 15%; observed motorboat activity is weighted 0% because no defensible lake-level measurement exists. Where a component has no data the remaining weights are renormalized and the confidence rating is lowered; below Medium confidence no number is shown. Sources: MI DNR bathymetric survey outline (0 ft isobath), USGS/MRLC NLCD Land Cover (2021), MI DNR Watercraft Control Areas (2026-08), MI DNR Boating Access Sites (2026-08) and MDOT Annual Average Daily Traffic (2025). Conditions change quickly — check current weather and local conditions before going out.

Non-native species records

No non-native species recorded in the available dataset. This does not confirm that no non-native species are present.

Source: Midwest Glacial Lakes Partnership Conservation Planner; underlying nonindigenous species records from the USGS Nonindigenous Aquatic Species database.

At the lake

community-mapped amenities · straight-line distance

⛻ Campground≈1.4 mi · 2 mapped

From OpenStreetMap community mapping — shown only where something is mapped; an amenity missing here may still exist. Distances are straight-line. Verify before you rely on it. © OpenStreetMap contributors (ODbL).

Bait & tackle nearby

licensed retail bait dealers · straight-line distance

Tab's Custom Cuts≈3.7 mi14500 Holmes Rd, Gregory · Google · Apple

Mike and Tina's Party Store≈5.9 mi · (517) 985-604413100 Territorial Rd, Stockbridge · Google · Apple

Lightning Quick Gas N Go #26≈8.3 mi4400 Clear Lake Rd, Grass Lake · Google · Apple

Dealers licensed by the Michigan DNR to sell live bait; listing is not an endorsement. Distances are straight-line, not driving — and call ahead: hours and stock change. Source: Michigan DNR retail bait dealer data.

Quick answers

Sullivan Lake — common questions

How deep is Sullivan Lake?

The deepest contour on the Michigan DNR bathymetric survey of Sullivan Lake is 22 ft. That is the deepest depth the historical survey map records, which may differ from the deepest point of the lake itself.

How big is Sullivan Lake?

Sullivan Lake covers about 20 acres in Washtenaw County, Michigan.

What is the average depth of Sullivan Lake?

The estimated mean depth of Sullivan Lake is 12.1 ft, calculated from the survey contours.

Is there public access to Sullivan Lake?

Yes. The Michigan DNR boat-launch data identifies 1 public access site on Sullivan Lake, including Sullivan Lake.