Inauguration Day normally entails an extra paid holiday for federal workers in the Washington area, but no such luck applies this year. That’s because the public swearing-in ceremony coincides with another federal holiday — the Jan. 21 observance of the birthday of Martin Luther King Jr.

That means the historic event — the first African American president taking the oath of office on a holiday commemorating one of the nation’s most notable civil rights leaders — will cost the region’s government employees a quadrennial holiday, at least in terms of pay and leave.

The official Inauguration Day takes place every four years on Jan. 20, except when the date falls on a Sunday, as it does this year. When that happens, the federal holiday moves to the following Monday.

Since the observance of King’s birthday falls on the same day, government workers in the D.C. area will lose the extra paid time off they usually receive for the swearing-in ceremony.

Full-time federal employees are entitled to “in lieu of” holidays, meaning they can normally bump the dates forward or back when official holidays fall on non-workdays. But that won’t apply this year because the law doesn’t offer such a provision for the inauguration holiday.

The reason: It’s not necessary.

The government provides a holiday for the swearing-in to relieve some of the logistical problems — such as traffic congestion and security — associated with the event, which draws massive crowds. That’s also why the holiday applies only to federal workers in the D.C. area instead of nationwide.

The extra day off won’t be needed to keep things running smoothly, because the King holiday eliminates the usual weekday crush of commuters and workers.

Some federal employees will have to work Jan. 21 despite the holiday. Agencies can decide which, if any, employees need to work that day.

Workers who have to show up on holidays include law-enforcement officers, firefighters, medical personnel, meteorologists and watch-center operators.

When Inauguration Day falls on a Sunday, the chief justice can administer the oath of office privately that day and publicly the following Monday. That’s how the process will take place this time around.

This year marks the seventh time in U.S. history that the constitutionally mandated inauguration date has fallen on a Sunday, with the last instance occurring during President Ronald Reagan’s second inauguration in 1985, according to a press release from the office of Sen. Charles E. Schumer (D-N.Y.), who chairs the Joint Congressional Committee on Inaugural Ceremonies.

Perhaps more notable is the symbolic importance of President Obama taking the oath of office on the King holiday.

“It works so well together,” said Hilary Shelton, senior vice president of policy and advocacy for the NAACP and director of the organization’s D.C. bureau. “It’s a wonderful thing, because so many people that support Dr. King’s legacy and believe in his dream will be coming to this inauguration.”

Shelton said Obama’s efforts on job creation, hate-crime prevention, public education and access to health care align with the mission of the late civil rights leader, who was assassinated in 1968.

“Many people see the agenda President Obama has worked so hard to push forward as something that supports Dr. King’s vision,” he said. “If we look at the agenda put forward by this administration, we see a direct correlation with what Dr. King worked for and died for.”