Watkins Mill High School. I don't go there anymore, but they filmed there when I did. It's a big forest separating Germantown and Montgomery Village, where they filmed some scenes. They used Seneca Creek State Park for a lot of the other stuff. And they edited the film on the Montgomery College campus.
Fine. It looks like a rip off of the Ring, but I'll still go see it tonight. Then I can come back and post if it really is like the ring or if the previews just made it out that way.
Keep in mind that ghost/curse stories are common in Japan. There have been dozens of similar movies, not because they are ripping each other off, but because that is the form that their ghost stories take.