The purchasing managers index rose 3.1 points to 55.7% in October, The Institute for Supply Management said.
A reading above 50% is considered a sign of future expansion. It was the PMI's highest level since April 2006. Computer & Electronic Products was among the sectors reporting growth.
New orders slipped 2.3 points to 58.5%, still well above the benchmark for growth. Production was at 63.3%, up 7.6 percentage points. Backlogs were flat at 53.5%, while prices grew 1.5 points during the month.
The ISM employment index jumped to 53.1, up 6.9 points. Employment also was at its highest point since April 2006, and topped the 50% mark for the first time since July 2008.