For a movie that evokes The Witch in terms of themes and atmosphere, check out The Blackcoat's Daughter. It's amazing, and beautifully crafted, but set in modern times, and not really bound up in any rural isolation, so possibly not what you're after.
For folk horror, you'll want something very different. Are you thinking of period movies specifically, or is it more a desire for the isolated-in-the-wilderness kind of vibe?
You'd almost certainly love the TV show Salem. Superb period horror. First season is best, but the second is decent too. It's about witches, witch trials, and gets gloriously horrific. If you want to watch a grotesque witch harvest a literal bag of dicks, watch season 2 of Salem.
I just saw The Alchemist's Cookbook, and while I didn't love it, it's a smart and interesting little movie that focuses on one man's descent into madness as he experiments with summoning spells, all alone in a tiny trailer in the woods. Definitely has that slightly folkish vibe.
Mr. Jones is pretty much the definition of folk horror set in contemporary times. It's about a couple living in the middle of nowhere who encounter an artist who creates horrific scarecrows for reasons.
And I forget the title, so perhaps someone else can help out, but another example of what I'd call folk-horror that comes to mind is a movie about two guys (brothers I think) who spend several nights in a cabin far away from civilisation. One is going through heroin withdrawal, the other is looking after him. They discover some artifacts, and a mystery unfolds. It has an interesting ending.
