We have a web application that gets deployed to multiple regions around our state. An instance of the application for each region. We maintain a staging and production (master) branch in our repository, but we were wondering what is the best way of maintaining each instances codebase. It's similar at the core, but we have to give each region the ability to make specific requests that may not make it into the core of the application.

Right now we have branches for each region, like region_one_staging, and region_one_production. At the rate we're growing we'll have hundreds of branches here in the next few years.

Is there a better way to do this?