Years ago, my parents took a ferry ride. They weren't my parents then, only a young couple, and the ferry was my father's idea of romance. He didn't know, and wouldn't know for several weeks, that my mother is terrified of drowning. Most children on the Eastern Shore of Maryland take lessons in ponds or pools or rivers, but my mother never learned to swim.

She was afraid, but not of him, so they went together on that quiet night down to Oxford, where they caught the ferry to Bellevue. Neither really remembers what followed, but it must have been some first date because a year later they became husband and wife, and a year after that they became mother and father, first to my sister, and then, over the years, to two more daughters.

I have taken that same ferry, from Oxford to Bellevue, many times. Not because it is useful—for the crossing is less than one mile—but precisely because it is useless. You can swim the channel or sail across it; you can even drive easily between Bellevue and Oxford.

Of the more than 200 ferries that still operate in the United States, some provide essential services between the mainland and islands not serviceable by bridge, road, or tunnel. Alaska's capital city has no roads connecting it to the rest of the state or the rest of the United States; the North Carolina Ferry System serves many islands on the Outer Banks that are unreachable except by sea.

Other ferries offer easier access than their land alternatives. Sixty thousand people take the Staten Island ferry every day in New York, more than 20 million per year, instead of commuting the 16 terrestrial miles. A few ferries, though, like the one between Bellevue and Oxford, continue to exist not out of necessity, but nostalgia.

OXFORD, THE LARGER OF the two towns served by this ferry, wades into the Tred Avon River. Almost all of its streets dead-end on the water—the asphalt slipping into sand, the sand slipping into mud, the mud mixing into the riverbed. Captain Samuel Tilghman was first given land here in 1658, and the town appeared on a map in 1670. In 1695, the area was surveyed on the King's behalf and then took his name, only Williamstadt didn't take, and the town continued to be known as Oxford. Like the town, the river that runs around it went by several different names, too: It was Thread Haven and then Third Heaven, and then, finally, the Tred Avon.

I have taken that same ferry, from Oxford to Bellevue, many times. Not because it is useful—for the crossing is less than one mile—but precisely because it is useless. You can swim the channel or sail across it; you can even drive easily between Bellevue and Oxford.

Oxford, once the name was settled, became quite the town. Its greatest son, Robert Morris, was sent by a Liverpool merchant to establish a trading center in 1738. Tobacco served as the only local currency until Morris instituted a monetary system that helped trade flourish. Before that, stray guineas and pieces of eight changed hands occasionally, but hard money was rare in a system that seemed to operate entirely on credit and pounds of tobacco. Slaves, convicts, and indentured servants arrived on the Shore, while tobacco, wheat, and lumber left. Whenever the tall ships came from Europe, they would fire their guns in celebration. One such celebration cost Morris his life: He died in July of 1750, struck in the right arm by the wadding of one of the Liverpool Merchant's cannons. He was buried east of Oxford, in the tiny cemetery of White Marsh Church.

A neighboring grave belongs to Reverend and Mrs. Daniel Maynadier, almost as famous as Morris, though not because of history but folklore. Hannah Maynadier became ill, but before she died she asked to be buried with her favorite ring. So valuable was the ring that once it was buried, two thieves tried to recover it, only the woman's fingers were so swollen that the ring got stuck. Mrs. Maynadier, not having actually crossed Charon's ferry, woke when the thieves cut off her finger. Prematurely pronounced dead, she scurried from the grave back to the rectory, for her husband was then the White Marsh Church rector, and they lived awhile longer until they were finally buried together years later, five years before Morris.

But one of Morris' sons, the one who shared his name, also shared his interest in money. That Robert Morris would become the financier of the American Revolution, serving first as chairman of the Second Continental Congress' Secret Committee of Trade and then as the nascent country's superintendent of finance. A signer of the Declaration of Independence, the Articles of Confederation, and the Constitution, the younger Morris' signature at least found a foothold in American history.

It was the Morris family who made the town of Oxford. Even when they were not there on the Shore, for the younger Morris lived mostly in Philadelphia, their influence made Oxford influential. By the middle of the 18th century, Oxford's size and stature rivaled Annapolis and even Baltimore. Throughout these years, the town's ferry went back and forth to Bellevue.

For the first 50 years, before the Morris economic system took, riders paid the fare in tobacco. The county commissioners authorized the ferry in 1683, giving Mr. Richard Royston 2,500 pounds of tobacco a year to operate it. Originally designed for men and horses, the ferry today carries mostly automobiles and bicycles. The crossing is three-quarters of a mile, and it's always been a busy stretch, at least on the Oxford side.

Bellevue isn't much to speak of, though the man who named the town named it for his wife, Belle. There was a packing plant, but that's gone. Like most of the Shore's granaries and canneries, it went away when consolidation took companies north and south, anywhere off the peninsula. Agriculture is still the biggest industry on the Eastern Shore, but what's grown here goes elsewhere to be processed and packaged.

Oxford, though, was once a great town. It had an icehouse, two stories tall, whose ice, stored in straw and sawdust so it didn't melt, came all the way from Maine. There were packing plants and warehouses for crops, shucking houses for oysters. There were tracks for racing horses and a military academy that was supposed to rival West Point and the Naval Academy. Gaslights were lit and brick sidewalks were laid, streets were numbered and a town newspaper was printed. The strand was full of boat builders who made bugeyes and skipjacks, grand oyster boats that sailed the Chesapeake Bay.

But the very revolution that put the Morris family in the history books saw the decline of the town as Baltimore stole shipping traffic. Oyster harvesting briefly brought a revival, but the oyster beds were depleted by the time the '20s roared. Blue crabs became a delicacy only after the oyster beds were emptied. Oxford was in like a lion, then out like a lamb. Today the town has fewer than 1,000 residents, a few restaurants, a little market, the strand, the yacht club, and, of course, the ferry.

Every day, same as always, from late spring until late autumn, that blessed ferry still runs. It is, at least by most calculations, the oldest privately run ferry in the United States. There were men who ran the ferry over the last 330 years, but there were also female captains. Amy Jensen ran the ferry in the first decade of its existence, and Judith Bennett inherited the ferry from her husband Thomas, then ran it herself before and after two other marriages; her son took over in 1725.

The earliest ferryboats were scullers, powered by oars and by sails. The William H. Fisher, a steam tug, started running the route in 1886; the small tug carried passengers, and towed a scow when there were wagons or horses. A gas tug called the Vivian took over in 1912, and ran until 1931, when finally a self-propelled ferry was commissioned and built specifically for the route in Oxford. The Tred Avon ran first on gas until 1950, when the engine switched to diesel and the wooden hull was extended to 56 feet to accommodate three cars.

That ferryboat was retired in 1974, replaced by another diesel-powered vessel, the Southside, which had run between Shelter Island and Long Island. The Talbot took over for the Southside and has run the route since 1980. Steel-hulled, the Talbot weighs 45 tons and has two 170-horse-power diesel engines; it's large enough to ferry 18 Mini Coopers at once, which it did once, to celebrate an anniversary. The ferry doesn't even turn around on its route: cars load from one end and unload from the other.

THE FERRY'S HISTORY IS local, but also personal. I took it many times as a child with my parents, whenever they were nostalgic. As children, we rushed the ferry gates, running off only to be picked up minutes later in the car. I thought then it was an epic crossing, and that the ferry was a fierce vessel. It wasn't and the ferry isn't, but that realization hasn't kept me from returning.

I remember taking the ferry once, on a date of my own. I thought I knew something then about desire and devotion, maybe even love, but I didn't. We were supposed to stop for ice cream at the little market in Oxford, but something silly like calories kept us from doing that, so we each had a plum as we crossed.

The modern ferry is swift—the crossing takes only eight or 10 minutes—and I don't even think we said a word during the crossing, just quiet looks back at the shoreline of Oxford and a quick breath of brackish air before getting back in the car to drive forward to Bellevue. The magic of that betwixt and between time when one thinks the ferry will go on forever. But it doesn't. Take a ferry with someone and rarely think of that person again; take that same ferry again with someone else and stay with that person for decades.

One bright June afternoon a few years ago, I took the ferry with my family, to celebrate my parents' 25th wedding anniversary. I kept having to raise my hand, and squint through my fingers to look at my parents. It was hard to remember that I was no longer a child, that they were no longer a young couple.

The captain renewed their vows on board, and afterward we ate lunch. Even then, in the warm light of the summer crossing, it was hard to see why their marriage lasts while so many others do not, why they cross backward and forward toward eternity while that simple scheme of crossing shore to shore is impossible for so many of us.