From Rap Dictionary
>===interjection=== up north
- Being up north means being in prison. The prison in question is Clinton Correctional Facility. It is about 250 miles north of NYC. 2Pac was imprisoned here, and gives a shout-out on "Picture Me Rollin".
- The north. "A Tribe Called Quest, we representing up north" -- A Tribe Called Quest (Motivators )
In Minneapolis, amongst Native American people, "up north" refers to the Ojibway Reservations in northern Minnesota, ie. Leech Lake, Red Lake, Mille Lacs, White Earth, etc.