The Shattuck Golf Club - Jaffrey, NH (Brian Silva, Architect)
If you miss a fairway or green, your ball falls off a cliff, on every hole. Built at the bottom of Mt. Monadnock in Southern New Hampshire.
Widow's Walk Golf Course - Scituate, MA (Dr. Michael Hurzdan, Architect)
Once again, very tight fairway, built around wetlands on an old quarry near the coast south of Boston.
While these courses are extremely tough, the are two of the most scenic rounds i have ever played. I'll keep going back no matter how many balls i lose!
I know these aren't on the top 100 list, but they are definitely in my top ten of most difficult to navigate.