The index, which measures business conditions in the industrial belt of Indiana, Illinois and Michigan, added 9.7 points to 59.7 after falling 3.4 points in the previous month.
Numbers above 50 indicate a business expansion.
The region's production index rose sharply from 49.9, which indicates a slight contraction, to 62.7, the highest level for that index since March 2012.
The capital equipment index, which shows how much firms are investing in production equipment, fell slightly -- from 114.2 to 109.9 -- but remained in expansion.
The employment index pulled out of contracting, rising from 48.7 to 56.9. The new orders index remained positive, climbing from 53.2 to 58.1.