Hemlock Falls is on the Hemlock Falls Trail in Kanawha State Forest. There seems to be several ways to access this trail. First is fron within the forest by travelling the Polly Hollow Trail to the Hemlock Falls Trail.
The other approach is from outside the park by way of Middle Fork Dr. (CR 15). To get there from US 119, take the exit for WV 219 and then go south and bear left onto Kanawha State Forest Dr. (CR 20). Drive .6 miles and turn right on Middle Fork Dr. (CR 15). Drive for 6.3 miles to the trailhead.
I attempted the second route and when I got close to the end, I had to turn around due to high water. Be warned that there are at least two creek crossing on this road that you must drive through. The first was not a big deal to me, but the second was looking pretty iffy, so I decided to save this for another day.
This is the dam you will pass when you first come into the park through the main entrance.