The manufacturing index, also known as the purchasing managers index (PMI), registered 53.5 in June, up from the reading of 52.8 in May, the Institute for Supply Management (ISM) said in a report.
A reading above 50 percent indicates the sector is generally expanding, while a reading below the ratio indicates contraction.
The ISM's new-orders index rose by 0.2 point to 56 in June, while the production index fell by 0.5 point to 54. The employment index continued rising in June, with the index rebounding by 3.8 points to 55.5, a positive sign for Thursday's employment report.
Except for oil and gas industry, most industries in the manufacturing sector reported stable improving business conditions, said the survey.
Eleven of the 18 manufacturing industries tracked by the ISM reported growth last month, while four industries reported contraction in the month, including petroleum and coal products, primary metals, plastics and rubber products and machinery industries.