Nature wrought the inlet that separates this narrow strip of dunes and brush from Ocean City just to the north, but humans have sought to control the shifting sands ever since.
If not for routine dredging, the gap cut during a 1933 hurricane might have filled in decades ago. In the meantime, millions of dollars have been spent to move around massive piles of sand on both sides of the inlet. As sand erodes from Ocean City beaches, man-made jetties block it from naturally reaching northern Assateague.
The resort town's leaders must act to protect the business of the beach. Facing higher storm surges and more frequent flooding, they are working to protect property and prepare residents.
But on Assateague, park rangers are ready to give up the fight.
Though change is constant on one of the Atlantic coast's few unspoiled barrier islands, Assateague's future is especially uncertain amid rising sea levels and other effects of climate change. To prepare, the National Park Service is considering long-term plans that could change the shape of the island, move more park activity to the mainland, and perhaps leave it accessible only by boat instead of a lone bridge that carries millions of visitors each year.
By the end of this year, officials could settle on a plan that would, in many ways, surrender decisions about the 37-mile-long barrier island to natural forces.
"So many changes are coming that we can't anticipate," said Deborah Darden, superintendent of Assateague Island National Seashore. "We're trying to make climate change organize what we're doing."
It is welcome news to Assateague lovers such as Joe Hoffman, 32, a Burtonsville native who has been visiting the island his whole life. On a recent sunny afternoon, as he sat in the shade of a beach tent, shirtless and in a floppy Orioles hat, he spied a beer can in the sand.
"There's no way the park can keep up with that kind of impact," the resident of Baltimore's Abell neighborhood said. "If less people were coming here ... I think that would be good for the island."
But would it be good for the island's loyal visitors? About 2 million come from across the Mid-Atlantic region and beyond each year, one-fourth the size of Ocean City's crowd. They are looking for a rare view of wild ponies, piping plovers and sika deer, or just an empty beach.
"I'd hate to see where it's cut off from so many people enjoying it," said Travis Wright, whose West Ocean City restaurant, the Shark on the Harbor, overlooks the northern tip of Assateague.
On nice days, he can see small boats dotting the beach, which looks barren compared with the Ferris wheel and condominium towers rising from Ocean City not far in the distance. In the winter, the ponies sometimes wander up that far.
"You hate to think about future generations where it's not going to be there," Wright said.
A place across
Assateague has changed greatly since native Pocomoke and Chincoteague tribes began visiting it in the 1600s, naming it a word that means "place across."
The north end of the narrow strip of land was once a half-mile wide, but by the mid-1990s, it was less than one-fourth of that, and more than a quarter-mile farther west. At its southern tip, where part of the island lies in Virginia, storms and surf continually reshape a hook formation just across the water from Chincoteague Island.
And yet, when national park officials in recent years began considering a new plan to guide park management, it was the first time they began to focus on the changes ahead.
The previous plan, adopted in 1982, resolved decades of debate over whether the island should be home to a colony of summer cottages, a restricted wilderness preserve or something in between.
More than 3,800 people had bought land for beach bungalows. By 1965, a bridge had been constructed connecting the island to the mainland. That is when President Lyndon Johnson decided to establish a national seashore there.
The designation meant those landowners had to sell to the federal government so it could conserve the island much as it had on Cape Cod, Cape Hatteras and Fire Island.
Still, conflict over the level of development in the park lingered over the nearly two decades that followed. The 1982 plan settled on what Richard Tousley, the park's superintendent at the time, called "restrained development" instead of more restrictive wilderness preservation.
Tousley's plan has molded Assateague into one of the most visited National Park Service seashore properties. Cars line up for miles to enter on the busiest days, filling up parking lots at beaches on the north end of the island. Tent and RV campsites fill up weeks in advance, and 12 miles of quiet beaches that are open to four-wheel-drive cars and trucks sometimes reach their capacity of 145 vehicles by 7 a.m.
Park officials hope to maintain that level of access. The problem, they acknowledge, is that climate change might prevent that. Storms such as Sandy in 2012 showed them it is only a matter of time before another historic storm alters the island's profile.
"It's dynamic now, and boy, it's going to get a lot more dynamic because of sea level rise and climate change," Darden said.
'Letting things go'
One of the biggest forces shaping islands like Assateague is known as overwash, when storm surge inundates them, eroding some areas while building up others. It is what tore the inlet that separates the island from Ocean City. Overwash, which repeatedly reshapes Assateague's southern tip, covered beach parking lots with 4 feet of sand during Sandy.
As seas rise and temperatures warm, that storm surge is expected to get more extreme.
By the time today's babies reach their mid-20s, scientists expect seas to rise from 3.5 inches to 9 inches higher at Assateague. With temperatures expected to rise 2 degrees to 3.5 degrees by 2040, on average, scientists also foresee more intense storms.
Park officials have seen fit to adapt. They have phased out brick-and-mortar bathrooms on the developed north end of the island in favor of semipermanent yet portable toilets that do not use plumbing and can be carted away with a forklift. When storms buried or washed away asphalt parking lots, they moved them inland and replaced the pavement with crushed clam shells, assuming that surf will one day wash them into the ocean or bays anyway.
Their preferred option for island management going forward calls for more adjustments.
If a storm knocks the Route 611 bridge out of commission, officials might decide not to repair it, replacing it with a ferry system. If heavy surf breaks a new inlet into Chincoteague or Sinepuxent bays, the channel might be allowed to remain even if it makes less of the island accessible to vehicles. And if sand buries existing campsites, officials might find a new spot for them on the mainland.
Under two other options, park officials would preserve existing recreation opportunities, and possibly prioritize them above protecting natural resources.
A fourth scenario calls for a hands-off approach, under which park infrastructure would not be maintained if lost or damaged in storms, eventually returning the island to a primitive state. Some conservation groups have endorsed that, but they acknowledge that it could be an unrealistic sacrifice for the public.
"I'm all about letting things go," said Jesse Miller, 36, a Taneytown resident who recently visited Assateague for the day. "I think they should keep it as wild as possible and maintain access."
A plan by winter
Park officials received more than 250 comments on the plans from the public this spring, and they expect to release revisions in the fall. A final plan should be adopted by early winter, Darden said.
But some elements are almost certain — including a $1.2 million annual project to add sand to beaches along the island's northern tip.
The rock jetties that maintain the inlet channel block sand from naturally replenishing the north end of Assateague. To make up for that, sand is dumped along the northernmost six miles of Assateague so it can deposit itself on shore. That will continue, Darden said.
Ocean City officials are among those who have weighed in on the future of Assateague, and for them, the more maintenance of the island, the better. Any changes to Assateague's profile, such as a new or widened inlet, could mean less protection for Ocean City from storm surge that pushes into Isle of Wight and Assawoman bays.
The town has invested in floodgates and educated downtown residents on flood forecasting, and is exploring how to better protect its water and sewer systems. Officials are not ready to consider any plans like Assateague's.
"There's a desire to try a different management approach on the south side [of the inlet] without knowing exactly what's going to happen," said Bill Neville, the town's planning director. "That uncertainty is something we're not quite comfortable with yet."
Baltimore Sun librarian Paul McCardell contributed to this article.