Also known as "Beyond The Clouds, The Promised Place," I found this after searching the Internet Movie Database for information on "Hearts of the West." In this English dubbed Anime, Japan's northern island, Hokkaido (also known as Ezo) is part of the Soviet Union, while the islands to the South are under the U.S.A. Middle school students, intrigued by a huge mast in Hokkaido, seek to visit across the forbidden border.
Things start to happen just before the Summer school break...
"5 Centimeters Per Second," another Anime by Makoto Shinkai