The Chicago Purchasing Managers' Business Barometer soared to 63.0 in April from 55.9 in March, the National Association of Purchasing Management-Chicago said Wednesday.
The data is compiled on a seasonally adjusted basis. An index reading below 50 signals a slowing economy, while a level above 50 suggests expansion.
Economists polled by Thomson Reuters predicted a 56.5 reading for the index.
The April reading was the fastest pace of growth for six months, led by sharp rises in new orders and production.
"April's gain, the second strongest outturn in two and a half years, left the three month trend in the barometer just below the 60 level, consistent with continued recovery of the US economy," according to a press release.
"New Orders and Production increased sharply, while improvements in Order Backlogs and Employment also added to the month's strong performance," the release noted.
