You've probably already read Stephen King's The Girl Who Loved Tom Gordon. If not, run don't walk - it's about a young girl who gets lost in the wilderness, and there's elements of horror though it doesn't totally fit in that genre. It's also just a really great book.
Rosemary Kirstein's "Steerswoman" series (4 books so far) has female main characters and unusual rural and wilderness settings, and book 3 has strong horror elements. It's about a world where a guild of proto-scientists called Steerswomen are bound to honestly answer any question they're asked, and anyone who meets them must honestly answer any question they ask or no Steerswoman will ever speak to them again. I don't think the first book is that great but the next three are phenomenal. It's best read unspoiled which is why I'm not describing the plot.
Re: Rec me a canon - books
Rosemary Kirstein's "Steerswoman" series (4 books so far) has female main characters and unusual rural and wilderness settings, and book 3 has strong horror elements. It's about a world where a guild of proto-scientists called Steerswomen are bound to honestly answer any question they're asked, and anyone who meets them must honestly answer any question they ask or no Steerswoman will ever speak to them again. I don't think the first book is that great but the next three are phenomenal. It's best read unspoiled which is why I'm not describing the plot.