The federal government wants to give away two historic Maine lighthouses — but not to just anyone.

Agencies interested in owning Boon Island Light Station, off York, or Halfway Rock Light Station, off Harpswell, must be committed to preserving the structures’ historical integrity and willing to try to make the islands they are located on accessible to the public, said Patrick Sclafani, spokesman for the U.S. General Services Administration in Boston.

People have until July 16 to submit a letter stating their interest, Sclafani said.

Eligible organizations will then be required by the National Park Service to fill out an application and will be given an opportunity to visit the lighthouse.

If there is no interest by a nonprofit organization, state or local government, historic preservation group or community development organization by the deadline, the lighthouses will be sold at auction.

Ram Island Ledge Light in Casco Bay was auctioned off in 2010 for $190,000 to Jeffrey Florman, a Windham brain surgeon, after there was no preservation groups showed an interest. Florman won the lighthouse in a coin flip with Portland real estate developer Art Girard.

“Historic lighthouses are unique in that they have sentimental and tangible value as historic landmarks in local communities. Through the preservation program, GSA helps find new stewards for excess lighthouses that are no longer considered mission critical to the United States Coast,” GSA’s Acting Commissioner of Public Buildings, Linda Chero, said in a statement.

Boon Island Light, which is about six miles from York, and Halfway Rock Lighthouse are both listed on the National Register of Historic Places.

The challenge facing the government, according to Earle G. Shettleworth Jr., director of the Maine Historic Preservation Commission, will be in finding an organization willing to invest the time and money to preserve the lighthouses and make them accessible to the public.

“Halfway Rock and Boon Island are both in the middle of the ocean and both are located on very small rock formations,” Shettleworth said.

He said he remains hopeful that a caretaker with an interest in history will step forward with a proposal.

The Boon Island lighthouse was featured in Kenneth Roberts’ 1956 novel “Boon Island,” and Shetteworth said it’s history is “extraordinary.”

In the novel, Roberts writes about what happened to the crew of the Nottingham Galley after the ship, which set out from London for Boston in 1710, struck Boon Island — at the time a desolate, lighthouse-less rock.

All of the crew made it to shore, but the ship and its cargo were lost. Stranded on the island without food or fire, the crew had to cannibalize a dead man before they were rescued.

Tim Harrison, who was president of the Rockland-based American Lighthouse Foundation for 13 years before leaving that post in 2007, said the group will submit a letter of interest for Boon Island.

“My guess is that no one will step forward for Halfway Rock and it will be purchased by a private individual with deep pockets,” said Harrison, who is also editor and publisher of Lighthouse Digest in Whiting. “But, as for Boon Island I can see an ideal partnership between the town of York and the American Lighthouse Foundation.”

Harrison said the two groups could charge people for helicopter rides to Boon Island, something that a preservation group in California is doing now to raise money for restoring St. George Reef Light.

York’s Town Manager Rob Yandow said the Board of Selectmen is scheduled to consider applying for ownership of Boon Island Light at the board’s June 25 meeting.

Yandow is not sure how the selectmen feel about the prospect of owning another lighthouse — the town already owns and maintains Cape Neddick Light, which is also known as Nubble Light – but he says selectmen must consider a number of factors.

“We don’t what the costs will be and then there is the liability issue to consider,” Yandow said. “Boon Island is isolated in the sense that you can’t just hop in a boat and go there. The island is mostly inhabited by seals.”

Cape Neddick Light is close to the mainland.

“You can throw a baseball from Sohier Park to the island,” Yandow said.

Harpswell Town Administrator Kristi Eiane said the Board of Selectmen met recently to discuss its interest in Halfway Rock Light and decided not to pursue ownership.

The lighthouse can be seen from Land’s End, a gift shop and rocky point at the tip of Bailey Island.

Eiane notified the Harpswell Historical Society about the lighthouse’s availability, but its president, David Hackett, said he doubts his group would be willing to take on such a financial burden.

“How could a little organization like ours raise enough money for the upkeep?” Hackett said. “I don’t see any way in the world that we could ever do anything with it.”

Hackett said that during high school he took a skiff to Halfway Rock several times to rake sea moss off its rocky ledges.

“It’s a hard place to get to,” Hackett said. “But it’s a beautiful structure. No doubt about that.”

Since the National Historic Lighthouse Preservation Act was passed in 2000, the GSA has conveyed 84 lighthouses to new stewards. Proceeds from the public auction sales are returned to the Coast Guard’s lighthouse fund.

In most cases, the Coast Guard continues to operate the lighthouse’s navigational beacons. That would be the case with Boon Island and Halfway Rock lighthouses.

According to the GSA’s notice of availability, Boon Island Light Station was put into operation in 1812.

The original tower was destroyed in 1831, but was rebuilt and replaced in 1855. At 123 feet, Boon Island’s is the tallest lighthouse on the Maine coast.

Halfway Rock Light Station is located about 10 miles east of Portland Head Light on a 2-acre rock ledge. The lighthouse, which became operational in 1871, is a 76-foot tall granite tapered tower connected to a boathouse.

The Maine lighthouses are among 12 lighthouses around the nation for which the GSA is currently seeking new owners.