From Cincinnati (1 hour):

I-74 to Hwy 52 north to Brookville, take Hwy 101 north to the Fairfield ramp (Old Hwy 101), turn left and follow it 2 miles until you see water.

From Indianapolis (1.5 hours):

(From I-70) Take I-70 to Richmond Exit #151 (Hwy 27 south), follow to Liberty. Take Hwy 101 south to the Fairfield ramp turn-off (Old Hwy 101), turn right. 

or

(From Hwy 52) Take Hwy 52 to Brookville, take 101 north to Fairfield ramp turn-off.

From Dayton (1.25 hours):

I-70 to Richmond Exit #151 (Hwy 27 south), follow to Liberty. Take 101 south to Fairfield ramp turn-off.