Federal law (5 U.S.C. 6103) establishes the following public holidays for Federal employees. Please note that most Federal employees work on a Monday through Friday schedule. For these employees, when a holiday falls on a nonworkday -- Saturday or Sunday -- the holiday usually is observed on Monday (if the holiday falls on Sunday) or Friday (if the holiday falls on Saturday).
2013  Holiday  Schedule
Tuesday, January 1New Year's Day
Monday, January 21Birthday of Martin Luther King, Jr.
Monday, February 18 *Washington's Birthday
Monday, May 27Memorial Day
Thursday, July 4Independence Day
Monday, September 2Labor Day
Monday, October 14Columbus Day
Monday, November 11Veterans Day
Thursday, November 28Thanksgiving Day
Wednesday, December 25Christmas Day


This year, the Inauguration Day holiday falls on Monday, January 21, 2013, which is also the legal public holiday for the Birthday of Martin Luther King, Jr. (See 5 U.S.C. 6103(c).)  For Federal employees who work in the District of Columbia, Montgomery or Prince George's Counties in Maryland, Arlington or Fairfax Counties in Virginia, or the cities of Alexandria or Fairfax in Virginia, Inauguration Day is observed concurrently with the Martin Luther King, Jr., holiday.  Federal employees in these areas are not entitled to an in-lieu-of holiday for Inauguration Day.
* This holiday is designated as "Washington’s Birthday" in section 6103(a) of title 5 of the United States Code, which is the law that specifies holidays for Federal employees. Though other institutions such as state and local governments and private businesses may use other names, it is our policy to always refer to holidays by the names designated in the law.

Taken from: http://www.opm.gov/policy-data-oversight/snow-dismissal-procedures/federal-holidays/#url=2013