Rust Belt
  
Iron. Ore. Steel. The middle of the country where they actually...make stuff. Instead of just talking about making stuff, like they do in D.C.
It's a belt-shaped area around and along the planes. The metals that got put together to make cars and planes and tractors and whatevers did well for a long time. The train-making era was our favorite. But then the world rained on the parade. (See: Planned Obsolescence. See: Idiot Management Who Ruined The Party. See: Idiot Unions Who Wouldn't Listen.)
So the rain rained and the metals in the belt rusted. Jobs went overseas. Profit margins declined. America lost its lead. We became just like everybody else in making stuff. So the metals in the belt...rusted.