Your credit report is compiled, maintained and distributed by three consumer credit reporting agencies (often known as Credit Bureaus), Equifax, Experian and TransUnion. Equifax is based in Atlanta, GA.
Experian is based in the United Kingdom with their U.S headquarters in Costa Mesa, CA. TransUnion is based in Chicago, IL. The data housed in each of these companies is proactively supplied to them by a large network of data furnishers, specifically credit grantors and collection agencies. The credit reporting agencies also access credit related public record data.