By law, employment at most U.S. Government agencies, including the Library of Congress, is limited to U.S. citizens. By Library regulation, the employment of non-citizens is only permitted if it can be demonstrated that there are no qualified U.S. citizens available for the position in question and that the individual falls within certain specified categories as determined by law. Only U.S. citizens are eligible for positions requiring a security clearance. More information about citizenship requirements may be found on the Library of Congress Web site.