(FORTUNE Magazine) – Ten years and over $400 million in the making, the first 370 miles of the East Coast Greenway officially debut next month. The Greenwhat? Greenway--an ambitious plan to link 2,600 miles of urban, suburban, and rural hiking and biking trails from the Canadian border in Maine down to the Florida Keys. The project is far from done, but 54 new or renovated paved trails, mostly in New England and the Mid-Atlantic, will be ready by June.

Similar in scope to the Appalachian Trail--but passing through dense population zones like Boston, New York, and Washington, D.C.--the East Coast Greenway (ECG) is largely funded by government grants earmarked for alternative transportation projects. "At the doorsteps of 30 million Americans, the Greenway will be a way for people to easily escape the built environment," says Karen Votava of the East Coast Greenway Alliance. And they'll be able to do it with ease: When finished, the ECG will include direct links with 27 Amtrak stations.

An additional $1.5 billion is needed to complete the remaining 80% by its 2010 target date. Politicians from both parties and a slew of philanthropic organizations have teamed up to seek White House support. Senator Susan Collins (R-Maine), one of 23 East Coast Senators who signed a pro-Greenway letter delivered to President Bush late last year, points out that it will help in "reducing the need for foreign oil and promoting a healthier lifestyle."

Maybe that's overstating the Greenway's impact. But surely some some Americans can be pried from their minivans for an afternoon. Across the Atlantic, on a similar new pathway, the Brits made some 97 million journeys last year alone.

For information and route maps see www.greenway.org

Feedback? atlast@fortunemail.com