5 CFR § 610.202 - Determining the holiday.
For purposes of pay and leave, the day to be treated as a holiday is determined as follows:
(a) Except when employees are entitled to a different holiday under 5 U.S.C. 6103(b)(3), an employee's holiday is the day designated by 5 U.S.C. 6103(a) whenever part of the employee's basic workweek (as defined in § 610.102) or basic work requirement (as defined in 5 U.S.C. 6121(3)) is scheduled on that day.
(b) When a holiday falls on a nonworkday outside an employee's basic workweek, the day to be treated as his or her holiday is determined in accordance with sections 6103 (b) and (d) of title 5, United States Code, and Executive Order 11582.
(c) When an agency determines the holiday in accordance with section 6103(d) of title 5, United States Code, for an employee under a compressed work schedule, the agency shall select a workday for the holiday that is in the same biweekly pay period as the date of the actual holiday designated under 5 U.S.C. 6103(a) or in the biweekly pay period immediately preceding or following that pay period.
(d) The provisions of section 6103(b)(3) of title 5, United States Code, on determining holidays for certain employees at duty posts outside the United States apply to covered employees who are working outside the United States at a permanent or temporary station or under travel orders. For the purpose of section 6103(b)(3), United States includes—
(2) The District of Columbia;
(3) Puerto Rico;
(4) The U.S. Virgin Islands;
(6) American Samoa;
(8) Midway Atoll;
(9) Wake Island;
(10) Johnston Island; and