Use Google Maps, or use my better directions:
Take Interstate 26 to exit 32 (old exit 23). It's the Unicoi exit. If you're heading east (coming from Johnson City), take a left off the ramp. If traveling west (coming from NC), take a right. You will immediately come to a stop sign, where you will turn right. This is TN-173. You will drive about .7 miles, where you should see TN-107 on the left. Turn there. Go about 7.3 miles, where you will see a brown wildlife viewing area sign. Turn right on the immediately following paved road. Turn right at the fork shortly thereafter. Drive no more than a mile and you will see a small gravel area on the right, along with a tree painted with a red blaze. This is where you will park.
Take the trail straight ahead, cross two creeks, then follow the trail downstream to the right. There are 3 or 4 different parts to these falls, but the largest of which will come first. It's about a 10 minute hike from the parking area.