What is this vine?
Unfortunately, this looks like porcelainberry, a non-native invasive plant in Maryland. You can look at Google images of it, and you'll notice that there is a lot of variation in the leaf shape. It is often mistaken for wild grapes. But, porcelainberry will outcompete native plants, smothering trees and killing them.
Here is our website info on it: http://extension.umd.edu/hgic/porcelainberry
Here is more extensive info from the Weeds Gone Wild website: http://www.nps.gov/plants/alien/fact/ambr1.htm
You can successfully get rid of it. It's just a matter of persistence. And this is a good time of year to start.