From Hill Library:
If you’ve ever used a service like InfoUSA or ZapData , you know how helpful it can be to generate a list of competitors or B2B prospects based on specific criteria. You also know how expensive it can be.
The Small Business Administration, it turns out, keeps tabs on a large group of businesses and provides access to these records at this site. Use the Dynamic Small Business Search site to bring up a list of businesses by state, county, NAICS code, ownership demographic, and all manner of other criteria.
These are companies that have shown interest in contracting with the government, so industry coverage will lean toward service and manufacturing. And not every company will be included, of course. Still, when the other option is a fistful of money, this company research tool isn’t too bad.