How about something like this? They can be broken down further depending on how many regions you want. I think I got all the states.
Region 1 (CT, MA, ME, NH, RI, VT,)
Region 2 (OH, MD, PA, WV, NY)
Region 3 (DC, DE, NJ)
Region 4 (AL, FL, GA, MS, SC,)
Region 5 (VA, KY, TN, NC)
Region 6 (IL, IN, MI, MN, WI)
Region 7 (AR, LA, NM, OK, TX)
Region 8 (IA, KS, MO, NE)
Region 9 (CO, MT, ND, SD, UT, WY)
Region 10 (AZ, CA, HI, NV)
Region 11 (AK, ID, OR, WA)
Plus, other countries...not sure how to group them. UK, Europe, Canada, ect. ??