I recently came across something about Nonnewaug Falls online, something from the book "New England Waterfalls: A Guide To More Than 400 Cascades and Waterfalls:"
Nonnewaug Falls from the main site: New England Waterfalls accessed June 30, 2010
Falls Road, Bethlehem CT 06751 is the best address to use as a destination if you are using a website or GPS device to find Nonnewaug Falls. Nonnewaug Falls Open Space Preserve is near the border of Watertown and includes a portion of land in Bethlehem, but is mostly located in Woodbury CT. It was a gift to the town by Harold Leever as well as a gift from the Creator to the many generations of Native People who lived, and still live, nearby - a Scared Place for thousands of years.
Here is a map or two I've made, always including the very large Oak Trees which have stood at the fork in the trail that Falls Road turns into. These oakes mark the place where you travel the path along the edge of another working hayfield toward the opening in the hemlocks that shade the Upper Falls at Nonnewaug.
Please respect the farmer and his crop. You wouldn't like it if he walked across your garden with no regard for your plants!