The tower is only 23 feet tall, but feels like a giant in the Kennebec River.

A visitor traverses a long wooden bridge, connecting the grassy mainland to the pudgy Doubling Point Light. Water rushes below, and one immediately senses the power of the river and the purpose of the light.

Doubling Point Light was built in 1898 on the northwest end of Arrowsic Island, on a sharp double bend in the river. For more than a century, it has served as an important aid to navigation for boaters heading up the river to Bath.

On Saturday, along with two dozen other lighthouses in Maine, the Doubling Point Light will be open to the public as part of the Maine Open Lighthouse Day.

Presented in a partnership among the U.S. Coast Guard, the state of Maine and the American Lighthouse Federation, the open house is the largest of its kind in the country.

This is the fifth year that Maine has opened some of its most picturesque and popular lighthouses to the public. Visitors have the unique opportunity to step into the romantic world of the lighthouse keeper, and to get a sense of the history and legacy of the beacons that dot Maine’s coast and inland waterways.

In all, more than two dozen lighthouses and their grounds will be open from Wood Island at Biddeford Pool in southern Maine to West Quoddy Head in Lubec, far Down East.

Open Lighthouse Day has proven enormously popular, said Bob Trapani, executive director of the Rockland-based American Lighthouse Federation. He expects between 12,000 and 15,000 people will visit a Maine lighthouse on Saturday.

Predictably, some lighthouses are more popular than others. Pemaquid Point in Bristol, Bass Harbor at Mount Desert and West Quoddy Head in Lubec draw huge crowds.

Others, such as Doubling Point and the Kennebec River Front Range Light, both in Arrowic, attract fewer people. “But what jewels they are,” Trapani said. “Sometimes those jewels are overlooked.”

Several offshore lighthouses, which can only be reached by boat, also are less popular. For instance, the Sequin Island light off Popham Beach in Phippsburg is best accessed via the Sequin Island Ferry. Once there, visitors can tour both the lighthouse and its first-order Fresnel lens — the only one of its kind in Maine — as well as the keeper’s house.

The lighthouses and grounds are open for guided and self-guided tours from 9 a.m. to 3 p.m. Saturday.

In addition, the Maine Lighthouse Museum in Rockland is open 10 a.m. to 4 p.m. Saturday. The museum is home to the largest collection of Fresnel lenses on display in the United States.

Staff Writer Bob Keyes can be reached at:

bkeyes@pressherald.com

Twitter: pphbkeyes

THE FOLLOWING are lighthouses in southern Maine that will be open during Maine Open Lighthouse Day. For a list of participating lighthouses statewide, go to tinyurl.com/openlighthouseday.

BASS HARBOR HEAD LIGHT

LOCATION: Lighthouse Road, off Route 102A, Bass Harbor

YEAR BUILT: 1858

HEIGHT: 32 feet

ILLUMINATING FACT: According to family legend, the 3-year-old grandson of the lighthouse’s first keeper, John Thurston, fell from a window of the lighthouse but was snatched up by his long dressing gown before hitting the rocks below.

BURNT COAT HARBOR LIGHTHOUSE

LOCATION: Lighthouse Road, Swan’s Island

YEAR BUILT: 1872

HEIGHT: 32 feet

ILLUMINATING FACT: The first keeper, F.A. Allen, and his wife lived at the lighthouse with their nine children. The light used to have a twin, but one was taken out in 1884 after mariners complained that the twin lights were confusing.

BURNT ISLAND LIGHT STATION

LOCATION: Entrance to Boothbay Harbor (offshore)

YEAR BUILT: 1821

HEIGHT: 30 feet

ILLUMINATING FACT: This is the second-oldest lighthouse in Maine that hasn’t been rebuilt. (The oldest is Portland Head Light, built in 1791.)

CURTIS ISLAND LIGHTHOUSE

LOCATION: Curtis Island, Penobscot Bay

YEAR BUILT: 1835

HEIGHT: 25 feet

ILLUMINATING FACT: The island is named after publishing magnate and philanthropist Cyrus Curtis, who summered in Camden.

DICE HEAD LIGHT

LOCATION: Battle Avenue, Castine

YEAR BUILT: 1828; rebuilt several times

HEIGHT: 51 feet

ILLUMINATING FACT: The lighthouse was sold in the 1930s, but has been restored by the town of Castine, and was re-lighted in 2008.

DOUBLING POINT LIGHT STATION

LOCATION: Doubling Point Road, Arrowsic Island

YEAR BUILT: 1898

HEIGHT: 23 feet

ILLUMINATING FACT: In 1999, the tower was lifted off the foundation with a crane, put on a barge and moved into storage while contractors reset the 12,000-pound granite blocks at the base.

FORT POINT LIGHT

LOCATION: Fort Point Road, Stockton Springs

YEAR BUILT: 1857

HEIGHT: 31 feet

ILLUMINATING FACT: This squared light tower was named for nearby Fort Pownall, and is attached to the keeper’s house by an enclosed passageway.

GRINDLE POINT LIGHT

LOCATION: Ferry Road, Islesboro (ferry from Lincolnville)

YEAR BUILT: 1874

HEIGHT: 39 feet

ILLUMINATING FACT: Located on picturesque Gilkey Harbor, the light keeper’s house is home to the Sailors’ Memorial Museum.

KENNEBEC RIVER RANGE LIGHTS

LOCATION: Doubling Point Road, Arrowsic

YEAR BUILT: 1898

HEIGHT: 13 feet and 21 feet

ILLUMINATING FACT: These are the only pair of “range lights” among Maine’s 64 lighthouses, and are among the very few wooden lighthouses in the country. The front light flashes continuously, while the back light shows six quick flashes, then pauses.

MARSHALL POINT LIGHTHOUSE

LOCATION: Marshall Point Road, Port Clyde

YEAR BUILT: 1832; rebuilt in 1858

HEIGHT: 24 feet

ILLUMINATING FACT: The scene only lasted a few seconds in the film, but during the title character’s cross-country run in “Forrest Gump” (1994), the Marshall Point Lighthouse made a cameo as the eastern-most point of his journey.

MONHEGAN ISLAND LIGHTHOUSE

LOCATION: Monhegan Island. Take a boat from Port Clyde, New Harbor or Boothbay Harbor. Open 11 a.m. to 4 p.m. Saturday.

YEAR BUILT: 1822

HEIGHT: 47 feet

ILLUMINATING FACT: Originally, the light came from burning sperm whale oil. Now, it’s powered by solar panels.

OWLS HEAD LIGHTHOUSE

LOCATION: Owls Head Light State Park, Owls Head

YEAR BUILT: 1825; rebuilt in 1852

HEIGHT: 30 feet

ILLUMINATING FACT: This lighthouse still uses a Fresnel light, which was installed in 1856 and produces a fixed white beam.

PEMAQUID POINT LIGHTHOUSE

LOCATION: Route 130, Bristol

YEAR BUILT: 1827; rebuilt in 1835

HEIGHT: 38 feet

ILLUMINATING FACT: This lighthouse appears on the Maine state quarter issued in 2003.

PORTLAND BREAKWATER LIGHTHOUSE (BUG LIGHT)

LOCATION: Bug Light Park, Madison Street, South Portland

YEAR BUILT: 1855; rebuilt in 1875

HEIGHT: 26 feet

ILLUMINATING FACT: This tiny lighthouse helps guide ships into busy Portland Harbor. It got its nickname, “Bug Light,” because of its small size.

PORTLAND HEAD LIGHT

LOCATION: 1000 Shore Road, Fort Williams Park, Cape Elizabeth

YEAR BUILT: 1791

HEIGHT: Original tower, 72 feet; raised 20 more feet in 1865

ILLUMINATING FACT: Photogenic Portland Head, located at the entrance to Portland Harbor, was commissioned by George Washington and was originally lit with 16 whale oil lamps. It’s one of the most photographed lighthouses in the United States.

ROCKLAND BREAKWATER LIGHT

LOCATION: On a granite breakwater in Rockland Harbor. Turn onto Waldo Avenue from Route 1, then turn right on Samoset Road.

YEAR BUILT: First temporary light built in 1888; permanent light built between 1900 and 1902

HEIGHT: 25 feet

ILLUMINATING FACT: The light was made in New Zealand, and is visible for up to 17 miles.

SEGUIN ISLAND LIGHTHOUSE

LOCATION: Two miles offshore from Popham Beach; accessible via Fish ‘N’ Trip Charters’ Seguin Island Ferry or by private boat

YEAR BUILT: 1795; rebuilt in 1819 and again in 1857

HEIGHT: 53 feet

ILLUMINATING FACT: This lighthouse’s lens is an extremely rare 1857 First Order Fresnel lens made of 282 individual glass prisms. It’s also Maine’s tallest lighthouse, and is said to be haunted by a 19th-century keeper who killed his wife with an ax after being driven insane by her constant piano playing on the isolated island. (Some say they can still hear the wife’s playing too.)

SPRING POINT LEDGE LIGHT

LOCATION: At the end of a granite breakwater at Fort Preble in South Portland. Turn right off Broadway onto Pickett Street, then left onto Fort Road.

YEAR BUILT: 1898

HEIGHT: 54 feet

ILLUMINATING FACT: Keepers used to exercise by running 56 laps around the tower’s main deck, which they figured was about a mile.

WEST QUODDY HEAD LIGHT

LOCATION: Quoddy Head State Park, 973 South Lubec Road, Lubec

YEAR BUILT: 1808; rebuilt in 1858

HEIGHT: 49 feet

ILLUMINATING FACT: This lighthouse is located on the easternmost point of land in the contiguous U.S., so it’s the first part of the country to see the sunrise every morning.

WHITEHEAD LIGHTHOUSE

LOCATION: Entrance to Penobscot Bay, Whitehead Island (offshore)

YEAR BUILT: 1804; rebuilt in 1831 and again in 1852

HEIGHT: 41 feet

ILLUMINATING FACT: Ellis Dolph, the lighthouse’s first keeper, illegally sold spermaceti oil used for the light to businesses in Thomaston.

WOOD ISLAND LIGHTHOUSE

LOCATION: Biddeford Pool (offshore)

YEAR BUILT: 1808; rebuilt in 1835 and again in 1858

HEIGHT: 47 feet

ILLUMINATING FACT: At one time, a French bootlegger sold his hooch on the island to passing fishermen — until the night a drunken group of sailors burned his building down.

MAINE LIGHTHOUSE MUSEUM

LOCATION: One Park Drive, Rockland. 594-3301; mainelighthousemuseum.org

ILLUMINATING FACT: The museum is home to an impressive collection of lighthouse artifacts and mementos, including a number of rare Fresnel lenses.

SUNSET LIGHTHOUSE CRUISE

THE AMERICAN LIGHTHOUSE FEDERATION and its local chapter, the Friends of the Rockland Harbor Lights, will offer a sunset cruise from 4 to 7:30 p.m. Friday. It will include close-up views of five lighthouses: Owls Head, Rockland Breakwater, Indian Island, Curtis Island and Grindle Point. Tickets cost $45, and proceeds benefit lighthouse preservation.

RESERVATIONS ARE required. Visit lighthousefoundation.org or call 594-4174.