It seems that you know the place is not far away from Xian?! It is Mt. Huashan. It is in Huayin County east of Xian. The mountain is famous for its steep. There is an old saying that Huangshan only has one access from the begining to the end. It can be reached by bus from east bus station of Xian or tourist bus from the east square of Xian Railway Station. You can also take trains there. About 2 hours from the city proper of Xian. Wish you have a happy journey!