BEA Bureau of Economic Analysis Under U.S. Economic Accounts see Industry for Annual Industry Accounts and more.
County Business Patterns
Includes County Business Patterns (CBP), Metro Business Patterns (MBP), and ZIP Code Business Patterns (ZBP). "These three programs cover most of the country's economic activity...".
Current Industrial Reports (CIR) This site brings the Current Industrial Reports. “These surveys measure manufacturing activity in important commodity areas,” from the US Bureau of the Census.
ITA International Trade Administration...Industry Trade Data and Analysis See “Manufacturing and Services industry offices data pages:”.
Valuation Resources.com Industry Information Resources “Industry Information Resources is a free resource guide to industry-specific resources and data for over 400 industries.”.
IPL2 Industry The IPL2 "Industry" page has annotated listings of industries sites.