Where is Casco Bay?
What makes Casco Bay a great place to live—for sea creatures
The Clean Water Act says: Casco Bay Is a Special Place
Why is Casco Bay worth protecting?
What are the biggest challenges to Casco Bay?
How is climate change impacting Casco Bay?
How is Friends of Casco Bay tackling these threats?
How well do you know Casco Bay?
Casco Bay in Numbers
229 = Square miles of water that Casco Bay covers
578 = Miles of shoreline around the rim of the Bay
785 = Islands and exposed ledges in the Bay
3 = Percent of the landmass of Maine the Casco Bay watershed encompasses
236,483 = Number of residents in the Casco Bay watershed, from Bethel to the Bay (2010 census)
1 in 5 = Number of Mainers living in the Casco Bay watershed
Casco Bay Extremes
Deepest spot: Lumbos Hole off Harpswell is 200 feet deep
Tallest structure along the shore: The Wyman Power Plant smokestack on Cousins Island, Yarmouth, is 400 feet tall.
Oldest lighthouse: Portland Head Light was originally commissioned by George Washington and was built in 1791. The tower is 72 feet tall; the light itself is 101 feet above the ocean surface.
Coldest air temperature: minus 39 degrees Fahrenheit (also -39⁰ Celsius)
According to the Portland Press Herald (January 4, 2014), the record for the coldest air temperature reading ever in Portland was set on February 26, 1943.
In our water quality testing data we found other extremes:
Coldest surface water temperature: 26.6⁰F (-3⁰C)
Recorded below the pier at Southern Maine Community College in early March 2003 and late February 2005
Coldest beach in Casco Bay: Willard Beach
The average temperature in August, when the water tends to be the warmest, is 61.7⁰F (16.5⁰C).
A tongue of cold ocean water from beyond Portland Head Light curves toward shore here.
Warmest water: 86⁰F (30⁰C)
Found in late summer in the Cousins River estuary and in New Meadows “Lake” (actually, it is not a lake at all, it is part of the Bay, dammed by a causeway)
Hardest place for a fish to breathe: New Meadows “Lake” in Brunswick
For much of the summer there is zero oxygen in the depths of this dammed embayment. As you know, almost all marine animals and plants need oxygen.
Easiest place for a fish to breathe: Mere Point Landing, Brunswick
We found 14.9 milligrams of oxygen per liter (mg/l) of water here, a very healthy level of dissolved oxygen. Fish become stressed when oxygen levels fall below about 5 mg/l.
Casco Bay Islands
Largest inhabited island: Peaks Island, part of the City of Portland, has a year-round population of around 1,000, who are joined by 2,000-5,000 part-time residents and summer day-trippers. In the late 1800s, Peaks Island was known as the Coney Island of Maine, thanks to a boardwalk, theater, amusement park, and several hotels. Most of these structures are gone, but concrete observation towers remain, evidence of its use as a military outpost during World War II.
Island where you might see a polar bear (well in a museum): Eagle Island, summer home of Arctic explorer Admiral Robert E. Peary, who led the first successful expedition to the North Pole in 1908. (You also can find one at Bowdoin College, from which Peary graduated in 1877.)
Maine’s two newest towns are islands in Casco Bay: Long Island seceded from the city of Portland in 1993, and Chebeague Island, once part of Cumberland, became its own town on July 1, 2007.
Best nearly inaccessible attraction in Casco Bay: Fort Gorges is free and open to the public, if you can get there. A stairway to the pier deteriorated long ago; visitors either must beach a boat in the sandy shallows or scale the granite dock at high tide. There are changes afoot there thanks to the efforts of Friends of Fort Gorges.
What can I do to help protect this amazing place?
- Be a Friend of the Bay by supporting one of our programs or by making a membership donation.
- Volunteer with us.
- Stay up to date on issues facing the Bay by joining our email list.
- If you are a boater, pumpout your boat’s head using our mobile pumpout service.
- Maintain a healthy yard without pesticides and fertilizers that can wash into storm drains and out into the ocean.
- Report what you see while out on the Bay–we want to hear about the good, the bad, and the ugly of what you are seeing out there.
- There are plenty of individual actions you can take in your daily life.
- And by working together on these collective community actions, we can help pass on a healthy Casco Bay to the next generation.
* Casco Bay Plan 2016-2021 (2015): “CB has abundant maritime trades, a strong lobster fishery, and more than 800 documented marine species.”
** The Economic Contribution of Casco Bay, prepared for Casco Bay Estuary Partnership by Ryan D. Wallace, Rachel Bouvier, Laura M. Yeitz, and Charles S. Colgan, November 2017