5 Best Sights in Side Trips From Portland, Maine

About 5 miles long and 1½ miles wide, Chebeague (pronounced shah-big) has a year-round population of about 390, which more than quadruples in the summer season. Originally used as a fishing ground by Abenaki Indigenous people, the island later became a place known for stone slooping—those workers who carried ballast and granite for 19th-century ships, to be used in grand buildings. The island has a number of impressive Greek Revival homes built by them. There are a couple of small beaches, but most visitors come to spend time at the Chebeague Island Inn, where there's golf and tennis to play, and an excellent restaurant (with dreamy water views) open for lunch, dinner, or just drinks on the breezy porch.

Little wonder that the farthest island from Portland served by ferry service is also the most secluded and natural. Roads are unpaved, and most of the woods and beaches here are conservation land. Food isn't always easy to find here; there is only one store, and hours can be limited, so bring a lunch if you're looking to picnic. If a beach is on your agenda, head toward Stone Beach for great views of the nearby islands.

Though most of Great Diamond is closed to the public, the Inn at Diamond Cove welcomes visitors and offers plenty to do. Housed in what was once Fort McKinley, a United States Army coastal defense fort built in the late 1800s and retired in the 1940s, it’s a combination resort, with several eateries as well as private residences. Guests can play tennis and indoor basketball, lounge at the pool, or use the complimentary bikes. Visitors often take the ferry just for the day, or for dinner at the property's fine dining establishment, Diamond's Edge. The area is car-free, so if you're not staying at the Inn, be prepared to explore on foot or bring your own bike.

Meanwhile, Little Diamond can be accessed on foot at low tide via Lamson Cove, and is filled with private residences, many of which can be rented during the summer months.

Three miles long and 1 mile wide, Long Island lives up to its name in shape, and is home to 200 year-round residents (many of whom work in the fishing industry) and 1,000 summer dwellers. There are a few lovely beaches here, including South Beach, Andrews Beach, and Fowler Beach. A few country stores and a bakery can supply you with vittles for a picnic. Bike rentals are not available, so bring your own over on the ferry or rent a golf cart close to the ferry landing when you arrive.

Nearest to Portland (only a 15-minute ferry ride away), this is the most developed of the Calendar Islands, but it still allows you to experience the relaxed pace of island life. Explore an art gallery or an old fort, and meander along the alternately rocky and sandy shore on foot, or rent a kayak, bike, or golf cart once off the ferry. A number of spots are open for both lunch and dinner.

The Fifth Maine Museum, a small museum with Civil War artifacts, open only in summer, is maintained in the building of the 5th Maine Regiment. ( 207/766–3330  www.fifthmainemuseum.org  $8). When the Civil War broke out in 1861, Maine was asked to raise a single regiment to fight, but the state came up with several (the number eventually totaled 40), and sent the 5th Maine Regiment into the war’s first battle, at Bull Run. The museum also offers guidebooks for a two-hour self-guided tour of the World War II Peaks Island Reservation.