There are many commercial services that offer a free FEIN (Federal Employer Identification Number) search by company name across multiple states simultaneously. All return different results and amount of detail. Below are screenshots of a company name search in 3 different FEIN services. You can also view the results at this page.

The free portion of the service FEINSearch returns a list of companies with the corresponding city and state. The results list of companies on KnowX also only shows city and state but the list is longer than the FEINSearch, possibly because of redundancy. A search by name on freeERISA provides the FEIN, company address and phone number, whether the address is current and the NAICS (North American Industry Classification System) code number. Registration entitles you to 3 free searches. The freeERISA site elucidates the sources for the FEIN material, which is helpful for understanding the limitations of the database and why all FEINs aren’t listed.