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Map of Bigelow Hollow State Park (Mashapaug Lake)
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Shore entry

Bigelow Hollow State Park (Mashapaug Lake)

Connecticut, United StatesDirections
Open Water suggested0–12 m (0–40 ft) depthShore entry

Bigelow Hollow State Park (Mashapaug Lake) at a glance

Bigelow Hollow State Park (Mashapaug Lake) is a shore dive site in Connecticut, United States with depths of 0–12.2 m (0–40 ft). Typically most favorable Jul · from 3 years of archive data. Divers commonly see Brown bullhead, Crayfish, and Smallmouth bass. Check the latest conditions and entry details before you go.

Favorable window now· until 18:00 · sunset 17:50

Wind forecast for this hour · 13:00 · run 12 h ago
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Tap a factor for its source and model point

Site hazards: Boat traffic near the ramp, long gear carry, cold water below the thermocline, low visibility

Read the full hazards ↓

Dive windows this week

Lightest wind: Wed
Mon8:00–18:00 favorable

6 kn wind (6 kn wind)

Tue8:00–18:00 favorable

5 kn wind (5 kn wind)

Wed8:00–18:00 favorable

3 kn wind (3 kn wind)

Thu8:00–12:00 moderate, 12:00–18:00 favorable

8 kn wind (8 kn wind)

Fri8:00–12:00 moderate, 12:00–17:00 favorable, 17:00–18:00 moderate

8 kn wind (8 kn wind)

Sat8:00–9:00 moderate, 9:00–18:00 favorable

5 kn wind (5 kn wind)

Sun8:00–18:00 favorable

6 kn wind (6 kn wind)

Favorable windowModerate window— no window

Every forecast dive window each day, site-local time, from wind forecasts. Numbers under each bar are daylight averages.

First light 6:45 · Sunrise 7:14 · Sunset 17:50 · some windows run past sunset

Source: Open-Meteo wind · updated 26 Oct, 01:22 GMT-4

Forecast only — always assess conditions on site.

Compare this weekend’s windows near Bigelow Hollow State Park (Mashapaug Lake)

Forecast · NOAA tide model

Tide & slack timing

Loading tide predictions

Recent diver reports

Dated firsthand observations from divers — not current conditions.

No diver reports for this site yet. — one dated observation helps every diver after you.

Dived here today — did the forecast match?

What Divers Say

Known for: Crayfish, Smallmouth bass, Yellow perch
Best time: Summer and early fall mornings before boat traffic

Based on community reviews and site data. Conditions vary — always verify before diving.

Best months, historically

What conditions have historically been typical at this site, month by month — not a forecast.

  1. January, 74% of days have historically been favorable, wind has typically been 11 knots
  2. February, 81% of days have historically been favorable, wind has typically been 11 knots
  3. March, 72% of days have historically been favorable, wind has typically been 12 knots
  4. April, 87% of days have historically been favorable, wind has typically been 11 knots
  5. May, 87% of days have historically been favorable, wind has typically been 10 knots
  6. June, 96% of days have historically been favorable, wind has typically been 9 knots
  7. July, 97% of days have historically been favorable, wind has typically been 8 knots, historically most favorable
  8. August, 96% of days have historically been favorable, wind has typically been 8 knots
  9. September, 93% of days have historically been favorable, wind has typically been 8 knots
  10. October, 91% of days have historically been favorable, wind has typically been 9 knots
  11. November, 81% of days have historically been favorable, wind has typically been 11 knots
  12. December, 77% of days have historically been favorable, wind has typically been 10 knots

July has typically had the largest share of favorable days here. Conditions vary year to year — this is historical context, not a forecast.

Based on 3 years of archive data. Bar height shows the share of days each month whose conditions have historically scored favorably.

Marine life seen at this site

Species noted at this site — not a promise of what you’ll encounter.

Species seen here

Rough labels: “Commonly seen” usually means two or more recorded sightings near this site in public dive logs (GBIF), “Occasionally seen” one; “Seasonal” and “Rarely seen” come from dive-guide research. Not a measured rate.

Fills & rentals nearby

No dive shops mapped within 25 km (16 mi). Know one? Add it to the map.

Data updated July 2026

Site details

A designated scuba area on Mashapaug Lake inside Bigelow Hollow State Park in Union, one of the few Connecticut state park waters that formally permits diving. The dive access is a small cove about a quarter mile from the Mashapaug Lake boat ramp, over a rocky and sandy freshwater bottom with a maximum depth around 40 feet.

shore

Boat traffic near the ramp, long gear carry, cold water below the thermocline, low visibility

Reviews

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