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748-acre Cohasset Harbor fishing map with NOAA BlueTopo survey contours (90.3% measured, 97.83% assessed), charted rock and wreck structure, regional fish-survey occurrence, sourced forage timing and verified public access. The water tops out around 41 ft. The depth chart is built from real agency bathymetry referenced to NAVD88; directly measured coverage remains distinguished from source interpolation. The channels, holes and drop-offs come from the source data, not a distance-from-shore model. The season-by-season read for each species follows, from the map's own numbers.
The drawn water covers 747 acres wrapped in 14.4 miles of bank, with 18 islands in the mix. With a shoreline index of 3.8, this water is all arms and coves — edge habitat well beyond its acreage. About 77% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. The basin spans about 2.2 mi end to end and 1.7 mi across at its widest. Scituate Harbor sits 5 mi southeast — the closest neighbouring chart.
Spring puts striped bass in skinny water — 5 to 20 ft is the zone. As the season builds they drop to 12 to 41 ft, wintering in 12 to 41 ft. Summer striped bass concentrate at Surveyed channel edge, a good-rated drop-off around 35 ft. Warm-month bites cluster around early morning and the evening. A topwater walker at low light or a paddletail on a light jig covers the summer program.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 20 ft | dawn & dusk | Surveyed channel edge (17 ft) | 3-6 inch paddletail, Suspending minnow plug |
| Summer | 12 to 41 ft chart-limited; documented 25 to 60 ft | dawn & dusk | Surveyed channel edge (35 ft) | Topwater walker at low light, Paddletail on a light jig |
| Fall | 10 to 35 ft | dawn & dusk | Surveyed channel edge (35 ft) | Pencil popper, Baitfish swimbait |
| Winter | 12 to 41 ft chart-limited; documented 20 to 50 ft | midday | Surveyed channel edge (35 ft) | Slow paddletail, Bucktail near bottom |
When the water first warms, bluefish slide up into 3 to 20 ft. By summer they slide out to 5 to 30 ft, and by winter most fish are in 15 to 40 ft. If you only fish one area, make it Surveyed channel edge: a drop-off around 22 ft that scores good in summer. In summer the feeding windows fall in early morning and the evening. Keep a popper (early/late) or a metal jigs in the rips rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 20 ft | dawn & dusk | Surveyed channel edge (17 ft) | Metal (Hopkins/Kastmaster), Pencil popper |
| Summer | 5 to 30 ft | dawn & dusk | Surveyed channel edge (22 ft) | Popper (early/late), Metal jigs in the rips |
| Fall | 3 to 25 ft | dawn & midday | Surveyed channel edge (22 ft) | Pencil popper, Big metal |
| Winter | 15 to 40 ft | midday | open water | Metal jig worked slow (southern waters) |
Spring puts black sea bass in skinny water — 10 to 40 ft is the zone. As the season builds they drop to 10 to 41 ft, wintering in 12 to 41 ft. Spring black sea bass concentrate at NOAA charted underwater rock, a prime-rated rock pile around 11 ft. Warm-month bites cluster around midday and early morning. A bucktail + grub or a diamond jig + squid teaser covers the summer program.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | midday & dawn | NOAA charted underwater rock (11 ft) | Hi-lo rig + squid, 1-2 oz bucktail + Gulp |
| Summer | 10 to 41 ft chart-limited; documented 15 to 60 ft | midday & dawn | NOAA charted underwater rock (11 ft) | Bucktail + grub, Diamond jig + squid teaser |
| Fall | 10 to 41 ft chart-limited; documented 20 to 80 ft | midday | NOAA charted underwater rock (11 ft) | 3-4 oz vertical jig (deep), Double-teaser rig |
| Winter | 12 to 41 ft chart-limited; documented 40 to 100 ft | midday | NOAA charted underwater rock (12 ft) | Heavy hi-lo rig on deep wrecks |
Spring tautog (blackfish) on Cohasset Harbor hold shallow, usually 5 to 25 ft. They move out to 10 to 35 ft in summer and finish the year down in 12 to 41 ft. Put NOAA charted underwater rock first on the milk run — a rock pile near 8 ft that grades prime for spring. The feeding windows run early morning. The summer box starts with a 1/2-1 oz tog jig + crab.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 25 ft | midday & dawn | NOAA charted underwater rock (8 ft) | Tog jig + green crab half, Bare jig + clam (early) |
| Summer | 10 to 35 ft | dawn | NOAA charted underwater rock (11 ft) | 1/2-1 oz tog jig + crab |
| Fall | 8 to 41 ft chart-limited; documented 10 to 50 ft | midday | NOAA charted underwater rock (8 ft) | Tog jig + whole green crab, Old-school rig + double crab (deep) |
| Winter | 12 to 41 ft chart-limited; documented 30 to 70 ft | midday | NOAA charted underwater rock (12 ft) | Heavy jig + crab on deep structure |
Start shallow in spring: atlantic mackerel sit in 5 to 41 ft that time of year. They don't go far with the seasons — 8 to 41 ft covers summer, 10 to 41 ft covers winter. The spot to know is Surveyed channel edge, a drop-off in about 35 ft of water that rates good for atlantic mackerel in summer. Warm-month bites cluster around early morning and the evening. Throw a feather rig or a small vertical jig until the fish tell you otherwise.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 41 ft chart-limited; documented 5 to 45 ft | dawn & dusk | Surveyed channel edge (35 ft) | Mackerel feather rig, Small silver jig |
| Summer | 8 to 41 ft chart-limited; documented 15 to 80 ft | dawn & dusk | Surveyed channel edge (35 ft) | Feather rig, Small vertical jig |
| Fall | 6 to 41 ft chart-limited; documented 10 to 65 ft | dawn & dusk | Surveyed channel edge (35 ft) | Compact silver jig, Sparse feather rig |
| Winter | 10 to 41 ft chart-limited; documented 30 to 120 ft | midday | Surveyed channel edge (35 ft) | Small deep jig |
The spring pattern is a shallow one: atlantic cod in 8 to 41 ft. The depth story barely changes: 10 to 41 ft through summer, 9 to 41 ft in winter. The spot to know is NOAA charted underwater rock, a rock pile in about 8 ft of water that rates prime for atlantic cod in spring. Plan around early morning in the warm months. Summer baits: a heavy metal jig or a large soft-plastic jig gets it done.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 8 to 41 ft chart-limited; documented 20 to 100 ft | dawn | NOAA charted underwater rock (8 ft) | Diamond jig, Heavy bucktail |
| Summer | 10 to 41 ft chart-limited; documented 45 to 180 ft | dawn | NOAA charted underwater rock (11 ft) | Heavy metal jig, Large soft-plastic jig |
| Fall | 7 to 41 ft chart-limited; documented 25 to 140 ft | dawn | NOAA charted underwater rock (8 ft) | Diamond jig, Bucktail with teaser |
| Winter | 9 to 41 ft chart-limited; documented 50 to 220 ft | midday | NOAA charted underwater rock (11 ft) | Heavy vertical jig |
Structure-wise the chart holds 39 features, led in depth by Surveyed channel edge at roughly 35 ft.
Access data: Town of Cohasset — Cohasset Harbor public access. Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for Massachusetts waters are set by the Massachusetts DMF (recreational saltwater) — and special regulations can apply to Cohasset Harbor specifically, so confirm the current rules before you fish.
Check the official Massachusetts fishing regulations →
Cohasset Harbor is about 41 ft (12 m) deep at its deepest point. The depth chart is built from real agency bathymetry referenced to NAVD88; directly measured coverage remains distinguished from source interpolation. The contours reflect measured and quality-assessed source depths.
Anglers target striped bass, bluefish, black sea bass, tautog (blackfish), atlantic mackerel, atlantic cod on Cohasset Harbor.
NOAA charted underwater rock is the top-rated area: a rock pile in about 11 ft of water that rates prime for black sea bass in spring. Every other rated spot, per species and season, is on the map above.
For striped bass, the summer bite is best in early morning and the evening. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on Cohasset Harbor is regulated by the Massachusetts DMF (recreational saltwater). Check the official Massachusetts regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Scituate Harbor 5 mi · New Inlet 7 mi · Hingham Bay 7 mi · Jacobs Pond 7 mi · Nantasket Roads 9 mi · Sculpin Ledge Channel 11 mi · President Roads 12 mi · Broad Sound 13 mi · Oldham Pond 13 mi · Furnace Pond 14 mi · Nahant Harbor 14 mi · Cleveland Pond 14 mi
See how Cohasset Harbor stacks up: best striped bass lakes in Massachusetts · best bluefish lakes in Massachusetts · best black sea bass lakes in Massachusetts · best tautog (blackfish) lakes in Massachusetts
Browse all Massachusetts fishing maps. See every water on DepthScout. Bathymetry credit: NOAA BlueTopo (NAVD88; 90% measured, 8% source-interpolated). How we build these maps. Fish here with a sonar unit that logs? Send us your depth data and we'll improve this chart, credited to you. For fishing guidance only, never navigation.