Jordan Strauss / Invision / AP
The headline index unexpectedly jumped to 25.60 in July from 19.28 in June.
Economists estimated the number would decline to 17.0.
"The Empire State survey has generally appeared consistent with the rebound in growth and rebuilding of inventories that we see for Q2: its average level of 13.2 was the highest since Q112," said UBS's Sam Coffin.