As of Thursday, most of the 184.5-mile Chesapeake & Ohio Canal National Historical Park had been reopened in the wake of Tropical Storm Isabel, which plowed through the area last week.
Still closed was a 20-mile segment of the towpath from the Pennyfield Lock in Montgomery County to the Monocacy Aqueduct in Frederick County, Acting Superintendent Kevin Brandt said.
Even in areas open to the public, visitors might encounter hazards.
"For safety reasons, visitors are asked to obey area-closed signs and to follow the directions of park employees," Brandt said.
The Williamsport and Hancock visitor centers will open at their regular scheduled times beginning Saturday.
The Georgetown Visitor Center and the Cumberland Visitor Center also are open to the public during their scheduled times.
Saturday's event, "History in Motion," at the Lander Lockhouse in Frederick County, Md., will be held from 9 a.m. to 2 p.m. But cycling, fly-fishing and canoeing activities have been canceled.