nearest ocean beach:
pittsburgh - atlantic city - 5:45 drive time
charlotte - myrtle beach - 3:30 drive time
atlanta - tybee island - 4:00 drive time
pittsburgh is considerably further from an ocean beach, though it is only 2 hours to
presque isle state park's beaches on lake erie
however, all of them are long enough from the ocean that the average person ain't day-tripping to an ocean beach from any of them.
to me, a place isn't truly "coastal" if you can't wake up on a random summer saturday and say
"hey, it's gorgeous out today, let's go to the beach!"