Buzzfile is a comprehensive list of all business by state or nationwide that are mapped to Post majors/concentration areas; data provided by Dunn & Bradstreet’s 18 million U.S. businesses in 18,000 industries.
If you live in CT then you use the Employers in Connecticut by Major/Concentration chart. Click the number to be directed to the detailed list.
If you live in a different state from CT then use the Employers in the US by Major /Concentration. Then scroll down the state column and find your state. Click on your state and the report will filter to only presenting companies in your major and your state.