Approximately 250 miles, between 4 & 5 hours, driving.
Niagara falls is in NY.
The Niagara Gorge is approximately 11 kilometers (7 miles) long, stretching from Niagara Falls to the Niagara River Whirlpool.
approx. 62miles
18km
18 km long
really long for those who care
10 or 20 days
22,000 metres long
"Ever" is a very long time, and eventually it probably will. However, it's not going to be anytime soon. Niagara Falls is on the Niagara river, which carries water from lakes Superior, Huron, Michigan, and Erie to Lake Ontario. All of these lakes get filled from rivers and springs and rains just about as fast as they drain.
400 miles is the distance from Philadephia to Niagara Falls. It takes about 7 hours to drive.
about 350 miles
That would depend on where you started from.