Pursuant to the Treasury and General Government Appropriations Act, 2000, Public Law No. 106-58, section 605 (September 29, 1969), any judicial employee assigned in the continental United States compensated with federal funds must be a United States citizen or otherwise eligible for federal employment within the United States. A non-citizen of the United States may be employed by the federal judiciary to work for courts located in Puerto Rico, Guam, the Virgin Islands, Northern Mariana Islands and Hawaii. For additional information regarding the employment of non-United States citizens, consult the United States Office of Personnel Management web site at http://www.opm.gov/ or call the Office of General Counsel at the Administrative Office of the U.S. Courts at (202) 502-1100.
Citizenship requirements for applicants to state courts will depend on the individual state's laws; it would be wise to contact the court's clerk or administrator directly.