The Chicago Purchasing Managers Index (PMI) unexpectedly climbed to 68.6 in December, from 62.5 in November.
Analysts were expecting a December figure of 61.5.
The December reading is the highest level since July 1988 and represents the fifteenth consecutive month of expansion.
A reading above 50 indicates expanding activity, while a reading below suggests contraction.
Despite the strong PMI data and some encouraging jobs numbers, US stock are trading down.