As to a free database, some recommendations I can offer as being a business librarian for over 20 years I have been asked this question quite often.
1. I would first check to see if your local public library has a subscription to a database such as "Reference USA". This free database allows you to search by NAICS/SIC and you can conduct an advanced search to find business listings in your area. Often this database can be used at home.
More info on this database can be reviewed here:
I would also see if the public library has access to "Ward's Business Directory of U.S. Private and Public Companies"
2. "Manta.com" is another database that allows you to search via SIC:
3. A new service that offers a wealth of information:
Many databases also allow a free 7 day trial so worth trying out sites such as "Hoovers.com" to use for a week and then gather the information you need or decide to subscribe.
I hope the information provided is found helpful as please let me know of any additional questions/concerns you might have. Also if you could please take a moment to rate my assistance so that I can receive credit for helping you today.
I would still look at Reference USA as there is a wealth of information and it allows you to search by NAICS/SIC. The companies can also be searched by area as well as industry etc. Give it a look as all information is free and can be downloaded for use later.
Please contact customer service to go ahead and close the question if you still feel the info was not what you were looking for.
With the access to Reference USA, access is obtained via your public library but using this database can be done at your home as no need to step into a library at all (although I would suggest visiting as they will have business info that can be found helpful in your research). I use Reference USA often from my public library and can access from working from home 24/7. I would still recommend looking at this database as it is the best in my opinion of a "free public domain" database that offers company information that can be searched by advanced methods.
You can also save and download your information on your computer or flash drive.
I hope this suggestion helps in your research. If still not satisfied, please contact customer services again.
Under "How do I access"