Mme Sherri's Natural Forest, in Chesterfield NH. Wife and I went #hiking there this past weekend.
It's a relatively small place, but very beautiful and contains the stone remnants of a socialite's home from the 1920s & 30s. It's affectionately known as the ruins of a "castle", but I wouldn't go that far.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko