Tears welled unexpectedly in my eyes as I emerged from beneath a viaduct in Washington, D.C., and the city's skyline came into view. A feeling of relief washed over me; the end of the trail was at hand.

For seven days, several friends and I had been riding our bikes along the Great Allegheny Passage, a rails-to-trails path across southwestern Pennsylvania, and the C&O canal towpath, which follows the Potomac River from Cumberland, Md., to Washington. In all, we had pedaled 275 miles.

In many ways the bike trip, which we'd been planning for more than a year, was idyllic — breathtakingly beautiful scenery mixed with splendid isolation — a perfect antidote for our busy, often overcrowded lives.

Beginning at Ohiopyle on a rainy Saturday afternoon, we rode for more than 20 miles without seeing another cyclist, and only two roads intersected the trail. For two days, we followed Casselman River in southern Somerset County, climbing steadily toward the Eastern Continental Divide, where the Gulf of Mexico Watershed gives way to the Chesapeake Bay Basin.

In Cumberland, the river became our constant companion. For 185 miles, the trail hugged the Potomac, along which so much of our country's history unfolded. Just into Maryland, we rested at a Confederate graveyard in a farmer's field. Several soldiers were buried there, as well as a woman who served as a spy for the South.

Continuing southeast, the trail passed Fort Frederick, which served as an outpost in the French and Indian War; Antietam, the site of the bloodiest one-day battle in the Civil War; and Harpers Ferry, where abolitionist John Brown seized the armory in 1859, bringing national attention to the slave issue.

At night, we camped at primitive sites along the trail, our husbands running sag wagon with the supplies. There, at the end of each ride, we washed at the pump, unpacked and repacked our saddlebags, and rested. Sitting around a campfire at night, the sound of Potomac always with us, we recounted the details of our day.

The trip, in many ways, was restorative, but it was not without challenges: from flat tires to scrapes and bruises, from hungry mosquitoes to heat and humidity. The trail, spongy and rutted by rain, was more tedious than we had expected, and often times it required our undivided attention, as we dodged limbs and splashed through puddles. The acorn-size gravel that covered much of the trail (not crushed limestone, as the literature had reported) made for a bumpy ride.

Stopping for lunch — seven days of power bars and peanut butter and jelly sandwiches — we would stretch our sweaty selves across the bench of a picnic table, still feeling the vibration of the trail within.

On the fifth day, our challenges mounted, as trees downed by a tornado blocked our passage. Portaging the bikes over and through the debris, we saw no other cyclist on our 40-mile ride that day, only men on backhoes and skid-steer loaders clearing the trail. Around the campfire that night, we were grateful beyond words that we weren't on the trail when the twister leapfrogged across Maryland's Washington County.

Finally, on the ride into D.C., the going was easy, as we sailed downward on a well-groomed trail alongside the tumultuous waters of Great Falls, as the Potomac tumbled toward the Atlantic.

At the Washington, D.C., underpass, cooled by the concrete bridge that surrounded me, I began to relax deeply, knowing the end was near. Relief — and joy — overcame me. Living for seven days amid natural beauty, riding side by side with dear friends, camping with spouses who supported us at every turn, I felt fortunate to be so blessed. Thus the tears.