At the Antietam Creek campground on the C & O canal, there are about 10 - 12 sites in a line between the canal towpath and the Potomac river. One of the folks staying at site number 6 says there’s water there — I didn’t confirm, but it only makes sense. Several of the spots have trails to the river — the canal is dry there (unless it’s been raining). Seems like it could be a nice, easy place for a canoe / camping trip only about 2 hours from home.