In or to the eastern part of the United States or Canada (especially the coastal regions) from the west.
Originally with reference to the eastern origins of settlers migrating westward during the expansion of the United States and Canada in the 19th century.
The eastern part of the United States or Canada (especially the coastal regions), as regarded by inhabitants of the west.
Mid 19th century; earliest use found in Prairie Farmer. Apparently partly from back + east, and partly from back + east.