Boston’s Freedom Trail and the Emerald Necklace are generally well known and promoted widely. Perhaps lesser known, though no less important, is the Bay Circuit Trail. Through woods, farmlands, cranberry bogs, vernal pools, and busy suburbs, the Bay Circuit Trail links parks and open spaces in 57 Boston-area communities and offers a path to nature open to everyone.

The idea for the trail was conceived in the late 1920s by green space visionaries of the time, including Benton MacKaye, founder of the Appalachian Trail. The notion was to create a greenbelt to provide open space to Boston’s ever-expanding population.

Today, the trail circles Boston in a 300-degree arc that swings from Plum Island and Ipswich on Massachusetts’s North Shore, through Lowell, Acton, and Framingham, all the way to the Duxbury and Kingston beaches of the South Shore. This 200-plus-mile arc connects green spaces and passes through, or near to, several sites perfect for family outings.

Whether your family likes to hike, bike, walk, snowshoe or ski, you’ll be able to find a section of the trail to fit your adventures. Some properties even have opportunities to swim. Several are near or run through Mass Audubon sanctuaries and Trustees of Reservations properties, as well as wildlife refuges.

Among them are the Minuteman Bikeway in Lexington and Concord; Great Meadows National Wildlife Refuge and Walden Pond State Reservation in Concord; Moose Hill Wildlife Sanctuary and Moose Hill Farm in Sharon; and Crane Beach and Appleton Farms in Ipswich.

The management and growth of the trail is a work in progress. In the 1990s, the Bay Circuit Alliance, a nonprofit volunteer organization, was formed and oversaw the designation of 86 percent of the trail and 5,000 acres of new conservation land. In 2011, the Appalachian Mountain Club and The Trustees of Reservations took on a greater role with the Bay Circuit Alliance to protect and promote the trail and greenway, making it available to future generations.

More information and maps can be found at www.baycircuit.org.