Hanging Rock Tower is in Monroe County, West Virginia which is in the southeastern part of the state near the Virginia border. Here is a drawing of the roads leading to Hanging Rock.

For a more general map of the area:

Mapquest for Gap Mills / Waiteville area

Parking lot coordinates are N 37 30.590',  W 080 26.288'

From Paint Bank, VA turn off of route 311 onto county route 600 and proceed 11 miles to Waiteville, WV. Turn right onto Limestone Hill Road ( county route 15 ) and go 4 miles. On the left you'll see a sign for Hanging Rock.  Take the left
into the gravel parking lot.

From Waiteville, WV take Limestone Hill Road ( county route 15 ) 4 miles. On the left you'll see a sign for Hanging Rock. Take the left into the gravel parking lot.

From Gap Mills, WV take Zenith Road and proceed 3.5 miles to Limestone Hill Road. 1.4 miles after you turn left onto Limestone Hill Road, there will be a hairpin turn to the left. You will notice it has been widened to accommodate parking along the road. Your best bet is to proceed another 0.4 miles until you top the hill. At this point there will be a parking area above the road on your right, but you have to watch for it; it is easy to miss. It is a small gravel area that will hold 8 or 10 cars at most. If you start going down hill you have missed it. In November 2010 the forest service erected new signs at the parking lot. The tower is a hike of a little less than 3/4 mile from the lower parking area and between .8 and .9 mile from the upper lot. The hike from the upper lot is a little longer but somewhat flatter on the lower half. The trail entrance from this lot is marked with yellow paint which signifies the Allegheny trail.

From Rock Camp, WV turn onto Willow Bend Road. After 2.5 miles or so, watch for a turnoff back to the right for Zenith Road. Proceed about 8 miles and turn right onto Limestone Hill road. 1.4 miles after you turn left onto Limestone Hill Road, there will be a hairpin turn to the left. You will notice it has been widened to accommodate parking along the road. Your best bet is to proceed another 0.4 miles until you top the hill. At this point there will be a parking area above the road on your right, but you have to watch for it; it is easy to miss. It is a small gravel area that will hold 8 or 10 cars at most. If you start going down hill you have missed it. In November 2010 the forest service erected new signs at the parking lot. The tower is a hike of a little less than 3/4 mile from the lower parking area and between .8 and .9 mile from the upper lot. The hike from the upper lot is a little longer but somewhat flatter on the lower half. The trail entrance from this lot is marked with yellow paint which signifies the Allegheny trail.

 From Blacksburg, VA two people have submitted directions from Blacksburg

Route # 1 From Blacksburg, VA it's 45 miles. Take US 460 past Pembroke, turn
right on VA 635 toward White Rock; stay on this road past  the White
Rock area into Monroe County (where the road becomes WV 17). About a
mile after the Waiteville-community sign, turn left on Limestone Hill Road; go 4
miles. On the left you'll see a sign for Hanging Rock. Take the left into the gravel parking lot.
 

For a more rural route:

Route # 2 Take 460 West. After about 8 miles, turn right onto VA-42 (Bluegrass Trail) towards Newport. Go for almost 10 miles on VA-42, then turn left onto VA-658. Go for about 4 miles on 658, then turn right onto 632.  After only half a mile or so, turn left onto 658 again .After a little less than half a mile, turn left onto VA-636.  This is not well-marked-there is no stop sign, and the road almost makes a V (636 is on the left). VA-636 becomes a dirt road, and becomes windy and steep.  After about 3 miles, you enter Monroe County, West Virginia. 
After entering West Virginia, go about another mile and a half.  The dirt road will come out of the woods.  There will be a church up ahead on the right, a house that may have a rebel flag in front of you, and a road that curves to the left. Take the left-curving road (you'll pass the house with the flag on your right). Follow this road to a stop sign.  There will be a yellow house in front of you.  Take a right. Soon you'll come to another stop sign.  Turn right again.  This road is wider and well-paved. You'll only be on the well-paved road briefly.  There will be a sign for Limestone Hill Road.  Take the left onto Limestone Hill Road. Limestone Hill Road is paved, but not well.  It also becomes steep and windy. Take Limestone Hill Road for about 4 miles. On the left you'll see a sign for Hanging Rock. Take the left into the gravel parking lot.