The SBA’s Directory of Federal Government Contractors lists all prime contractors who are required to subcontract a certain percentage of their work to small businesses.
Once you’ve found a prime contractor in your field, go to their corporate website and look at their requirements to be a subcontractor.
The directory includes the name and location of the vendor, the contracting agency’s name, the contract’s product/service code (PSC) and North American Industry Classification System (NAICS) code; the state the contract will principally be performed in; the contract number (PIID); the contract’s performance start date and completion date, and the total contract value.