Yooper is a common term for residents of the Upper Penisula of Michigan. It is derived from the initials U.P. which is pronounced you-pee. U.P. stands for Upper Peninsula, as opposed to the lower peninsula of Michigan.
It is not a derogortory term. It is used mainly by residents of lower Michigan and Wisconsin.
That person is a yooper from Escanaba, Michigan.
Yoopers make fun of Trolls. Trolls are from 'down below', referring to lower Michigan.
Yoopers come from above the bridge, referring to the Mackinac Bridge, which separates upper Michigan from lower Michigan.
Yoopers have a habit of saying 'youse guy's' or often putting 'eh' after a statement. ie; Hey,youse guys, we're proud to be yoopers, eh?.