11 Best Sights in Hartford and the Connecticut River Valley, Connecticut

Housed in an 1878 steamboat warehouse, this museum tells the story of the Connecticut River through maritime artifacts, interactive displays, and ship models. The riverfront museum even has a full-size working reproduction of the world's first submarine, the American Turtle (named for its appearance); the original was built by David Bushnell, from nearby Westbrook, in 1775 as a "secret weapon" to win the Revolutionary War.

This strikingly modern building, designed by world-renowned architect César Pelli, houses 40,000 square feet of exhibit space under a wavelike roof that appears to float over the structure. Among the more than 165 hands-on exhibits, youngsters, teens, and adults alike can dive into a black hole and examine the moon's craters in the Exploring Space exhibit, race mini-sailboats and magnetic trains at Forces in Motion, and discover hidden athletic talents in the Sports Lab. Kid Space is perfect for ages three to six, and everyone enjoys mingling with free-flying butterflies in the Butterfly Encounter. Complete your visit by taking in a movie in the 3-D digital theater.

This excursion offers some of the best views of the Connecticut River Valley from a vintage steam locomotive pulled by 1920s-era coaches and an old-fashioned riverboat. The train, traveling along the Connecticut River through the lower valley, makes a 12-mile round-trip from Essex to Deep River Landing. Before returning by train to Essex, you have the option of boarding the Becky Thatcher riverboat and cruising along the river past Gillette Castle, Goodspeed Opera House, and fascinating deep-water coves and inlets. (The open promenade deck on the boat's third level offers the best views.) The train also hosts themed excursions such as the seasonal North Pole Express (from mid-November until Christmas).

The 122-acre park's main attraction is a rather outrageous, 24-room, oak-and-fieldstone hilltop castle—modeled after medieval fortresses of the Rhineland and built between 1914 and 1919 by the eccentric actor and playwright William Gillette. You can tour the castle (and its secret passages) and hike trails near the remains of a 3-mile private railroad, which chugged about the property until the owner's death in 1937. Gillette, who was born in Hartford, wrote two famous plays about the Civil War and was especially beloved for his play Sherlock Holmes (in which he performed the title role). In his will, he demanded that the castle not fall into the hands of "some blithering saphead who has no conception of where he is or with what surrounded."

This magnificent 1876 Victorian-gingerbread "wedding cake" theater on the Connecticut River—so called for its turrets, mansard roof, and grand filigree—is widely recognized for its role in the preservation and development of American musical theater. More than 20 Goodspeed productions have gone on to Broadway, including Annie and Man of La Mancha. Performances take place from May through December; one-hour Opera House tours are offered on the first Saturday of the month.

Looking for a quintessential New England outing? The Lyman family first settled on a 37-acre plot just south of Middletown in 1741; today, it's an 1,100-acre orchard that's not to be missed. Get lost in the sunflower maze, then pick your own seasonal fruits—berries, peaches, pears, apples, and even pumpkins—from June to October. Or stop by the Apple Barrel Market, open all year long, to shop for farm-fresh pies, fruit baskets, jams and preserves, and gifts.

Built in 1874, this was the home of Samuel Langhorne Clemens (better known as Mark Twain) until 1891. In the time he and his family lived in this 25-room Victorian "Stick Style" mansion, Twain published seven major novels, including The Adventures of Tom Sawyer, The Adventures of Huckleberry Finn, and The Prince and the Pauper. The home has one of only two Louis Comfort Tiffany–designed domestic interiors open to the public. A contemporary museum on the grounds presents an up-close look at the author and screens an outstanding documentary on his life introduced by Ken Burns. Tour size is limited; book online before your visit.

An important stop for art lovers, this 100-year-old museum's collection of more than 8,500 works, from 1740 to the present, focuses solely on American art. Among its treasures are paintings by John Singer Sargent, Winslow Homer, and Georgia O'Keeffe, as well as sculpture by Isamu Noguchi. Of particular note is the selection of Impressionist artists, including Mary Cassatt, William Merritt Chase, Childe Hassam, and John Henry Twachtman, as well as Thomas Hart Benton's five-panel mural The Arts of Life in America. The museum also has a café, a large shop, and a library of art books.

The more than 100 aircraft at this museum include gliders and helicopters, a World War II–era P-47 Thunderbolt, and a B-29 Superfortress, along with other vintage fighters and bombers—and an extensive collection of engines, instruments, parts, uniforms, and personal memorabilia. There's even a fighter-jet simulator. Next to Bradley International Airport, the museum also frequently holds open-cockpit days, allowing both young and old to play pilot.

The gold-domed State Capitol building, built in 1878 overlooking Bushnell Park, houses the state's executive offices and legislative chamber, as well as historical memorabilia. Walk past the statue Nathan Hale, the official state hero, to the Hall of Flags to see historic battle flags carried by Connecticut troops in wars from the Civil War through the Korean Conflict—along with a camp bed used by Marquis de Lafayette when he came to Hartford to meet with George Washington during the Revolutionary War. When the General Assembly is in session (January–early June in odd-numbered years; February–early May in even-numbered years), visitors can observe the proceedings from the public galleries. The League of Women Voters provides free guided tours each morning by reservation.

The nation's oldest public art museum—and the first American museum to acquire works by Salvador Dalí and Italian Renaissance artist Caravaggio—houses more than 50,000 artworks and artifacts spanning 5,000 years, along with 7,000 items documenting African American history and culture in partnership with the Amistad Foundation. Particularly impressive are the museum's Baroque, Impressionist, and Hudson River School collections.