It is about 45 km from Tallinn. However, write "Unallika" in Google maps and it will guide you to the place nicely.

Anyway, you can take the Padis monastery as the first landmark, then the road to Nõva, then you need to turn from Kõmmaste to Pae village and then, when you reach Pae village, to Harju-Risti. Well, after 150 meters you will be there :) If it all was too confusing, use Google maps :)

Call for any urgent questions!