U.S. 40 passes over Garrett Island, a 198-acre uninhabited island in the Susquehanna River. (Rachel Woolf/Baltimore Sun Video)

Heading into town from the west on U.S. 40, drivers take a bridge across the Susquehanna River and cut through treetops reaching up from another world below the rumbling road. It's green down there on Garrett Island, and busy with the activity of many creatures, if not people.

People have been pinning their aspirations on Garrett Island since the 1600s, when one Englishman talked about building a college there. But lately, these 198 acres are reserved chiefly for plants, trees and nonhuman actors. Deer make their home here amid the forest and marsh, along with songbirds, bald eagles, osprey, turtles, frogs and plump reddish spiders that seem bent on webbing all the low tree branches together. People are allowed by the federal owners to step ashore, but no farther — at least not yet.

The U.S. Fish and Wildlife Service wants to open the island up for more access and started work on a trail a few years ago, but the project stalled amid a shortage of staff and money. So all visitors can do is pull a boat up to a tiny stretch of sand on the east side, have a look around, and go on their way.

"It would be nice if people can use something that's practically in their backyards," said Cindy Beemiller, a U.S. Fish & Wildlife Service refuge specialist. Opening the island would "teach people about public lands — in our case, about refuges."

Beemiller and a colleague in 2011 marked some trees with tape as they considered possible pathways through Garrett Island, also previously known as Palmer's Island and, for a short, time Watson's Island. A detailed trail map was never drawn, but they had a general notion about a path.

It would lead from the beach to a narrow wooden boardwalk through a cattail marsh to higher ground, through the forest to the CSX railroad bridge built on cement pilings in the 19th century, past a mound of volcanic rock. Signs would point out natural and historic features of Garrett: Once populated by the Susquehannocks, erstwhile location of an early 1600s trading post hotly disputed between fur trader William Claiborne and Lord Baltimore, 19th-century fish-packing house, quarry, World War I military outpost.

That's the idea, anyway.

Other ideas have come and gone. One early 21st-century developer looked at Garrett Island and saw this spot in Cecil County — accessible only by water, maybe 400 yards from the boat ramp — as a great location for a hotel and conference center. Edward Palmer, an early 17th-century member of the Virginia Company of London, bought the island around the 1620s and thought it would make a fine place for an "Academy," according to one historical account.

A thorough wildlife survey hasn't been done, but the island is "typical eastern deciduous forest," said Matt Whitbeck, U.S. Fish & Wildlife Service biologist. It's part of the Chesapeake Marshlands National Wildlife Refuge Complex, consisting of land in Maryland and Virginia that also includes the Eastern Neck, Blackwater and Martin refuges. Thousands of acres in the complex are closed to the public, including all but a few square yards of Garrett Island.

See pictures of the island.

Whitbeck said the island is abundant with birds — blue grosbeak, indigo bunting, woodpeckers, Cape May warbler, Canada warbler, herons, ovenbirds — and basking grounds for the northern map turtle, a Maryland endangered species.

Richard A. Seigel, a Towson University biologist who has studied the map turtle, said the island either is home to a remnant of a once larger turtle population or it serves as a "nursery" of sorts for young turtles swimming down from hatching grounds in Port Deposit.

Seigel said the turtles can be found on logs and rocks around Garrett's edges, not on the island itself, and would not be disturbed by a walking trail. Still, if it is a "transitional" turtle habitat — confirming evidence of which is yet to be found — that would make the island an important spot in the map turtle life cycle, as the aquatic reptiles fortify themselves for a few years before heading back upstream to nest.

Unlike the islands to the south, Garrett is grounded in rock, not sand, and is not threatened by erosion. With a hill about 85 feet high, it's the tallest island in the Chesapeake, said Richard A. Ortt Jr., director of the Maryland Geological Survey. The often-noted feature of a remnant "volcano" is misleading, Ortt said, as that mound is really a pile of volcanic rock that was widespread in the area, left behind some 500 million years ago.

Garrett became part of the national refuge system in 2003, after local preservationists raised money to buy it for $750,000 from a developer in Pennsylvania, who had bought it for $250,000 from the CSX railroad. More than a century before, the island had been sold to the B&O Railroad, which built the stone and metal bridge and named the place for one of its presidents, John W. Garrett.

When the railroad owned it, Garrett was a summer playground for generations of nearby residents.

That's changed since the U.S. Fish & Wildlife Service took over and posted notices at the beach that the tiny landing is open from sunrise to sunset, but everything else is closed to the public. Officers from the federal agency and from the Maryland Department of Natural Resources patrol only "periodically," said Suzanne Baird, manager of the Chesapeake Marshlands National Wildlife Refuge Complex, but they've caught a few trespassers.

As recently as the Fourth of July weekend, Baird said officers charged a few people and fined them $150.

A steep price, lovely as the island is, sitting beneath U.S. 40 as the road rides the Thomas J. Hatem Memorial Bridge, with Garrett's rocky south end anchoring some of the bridge supports. Not quite another roadside attraction, but time will tell.

arthur.hirsch@baltsun.com

If you go

Take U.S. 40 or Interstate 95 to the Perryville town boat ramp, 501 Roundhouse Drive, Perryville. The beach landing area on the island is open to the public between sunrise and sunset. The rest of the island is off limits.

About the series

Postcards from U.S. 40 is a series of occasional articles taking readers on a summer road trip along the historic highway that stretches 220 miles across Maryland. Have a suggestion for where we should go next? Tell us about it at baltimoresun.com/US40Share. Follow the series at baltimoresun.com/postcards.