The Northern Blue Ridge is the simple, straightforward part of the massive Blue Ridge Mountain complex. Basically, it is just one, long mountain ridge stretching from Dillsburg, PA south to Roanoke, VA. There are complexities, of course, but in general this range is as close to being the ideal single simple chain of mountains as you will find. Indeed, the Northern Blue Ridge it is only crossed twice by rivers in its entire 300 mile length, at the impressive gorges of the Potomac and the James Rivers.
The centerpiece of this stretch of mountains is Shenandoah National Park.
North of the park is the low far northern Blue Ridge, and, north of the Potomac River, even lower but bigger South Mountain in Maryland and Pennsylvania. South of the park is a higher, wilder, and somewhat unknown 115 mile piece of the Blue Ridge.
The Appalachian Trail follows essentially the entire 300 mile ridge, on or near the crest the whole way, and the Skyline Drive in Shenandoah National Park and its continuation, the Blue Ridge Parkway to the south,
parallel the A.T. for over 200 miles. This enables car tourists to drive in a day what takes most though-hikers well over a week, even allowing for frequent stops at turnouts to admire views.