5 U.S.C. § 6104: Holidays; daily, hourly, and piece-work basis employees

on which agencies are closed by Executive order, or, for individuals employed by the government of the District of Columbia, by order of the Mayor; by administrative order under regulations issued by the President, or, for individuals employed by the government of the District of Columbia, by the Council of the District of Columbia; or solely because of the occurrence of a legal public holiday under section 6103 of this title , or a day declared a holiday by Federal statute, Executive order, or, for individuals employed by the government of the District of Columbia, by order of the Mayor;