Wiang Kosai is the first national park in Prae Province. It covers Long District and Wang Chin District, Prae Province and Tern District, Sobprab District and Mae Ta District, Lampang Province. There are crossed over by high steep mountains and many beautiful waterfalls, e.g. Mae Koeng Luang, Mae Koeng Noi, and also Mae Jork Hot Spring which is the source of rivers and streams. The area of the park is about 410 Km2 (256,250Rai).