The funny thing is there is an MD line that goes through Colorado separating two different Declination areas. I wouldn't worry about that line though as its a guideline and the difference from one side to the other isn't like "time zones" You aren't going to be off. I've flown on each side of it without doing a CC and it flew fine.
I live at 5800' ASL and have flown at nearly 11,000', have changed locations by several hundred miles and didn't redo my CC (unless it was drifting) with no issues.
Hah! I live 3' ASL

