Thousands of area residents will mark the 50th anniversary of the birth of the Rev. Dr. Martin Luther King Jr. today with memorial services large and small, and parade in King's honor down the southeast Washington avenue that bears his name.

The day is a holiday for nonemergency employes of the District of Columbia, Prince George's County and Maryland state governments. Virginia state offices will be closed as well, but to honor Confederate generals Robert E. Lee and Stonewall Jackson, not the minister and civil rights leader.

Public schools will be open in all jurisdictions except the District of Columbia, Montgomery County and Alexandria. In Alexandria, teachers must report to work despite the suspension of classes.

While most of his employes have the day off, Washington's Mayor Marion Barry will be a busy man if he can keep up with the schedule he faces.

After Barry delivers the keynote speech at the city's official observance of King's birthday -- 10 a.m. at the King library, 901 G St. NW -- he will rush across the Anacostia River and try to catch up with the parade before it reaches its destination, Covenant Baptist Church at 3845 South Capitol St. SE. The parade will begin at 10 a.m. at the "big chair" on the site of the defunct Curtis Brothers furniture store, 2041 Martin Luther King Ave. SE.

Barry is scheduled to address the marchers at the church shortly before noon, but he will not be the featured speaker. That honor falls to 12 Anacostia schoolchildren -- several of them born since King's assassination on April 4, 1968 -- who will talk about what King's memory means to them.

From Covenant Baptist Church, Barry will proceed to a reception party at the D.C. Armory for participants in both his inaugural parade and today's King memorial parade. Barry also plans to attend a memorial concert by Nina Simone at the Kennedy Concert Hall tonight.

Today's parade, which will include the Cardozo High School marching band and a contingent of D.C. sanitation workers who were with King in Memphis 11 years ago, was conceived by city Councilwoman Wilhelmina Rolark (D-8). Rolark hopes the parade will become an annual institution and spur area residents to "pay attention to what (King) stood for.

"Some people view him as controversial and divisive," said Rolark. "I'm hoping people are ridding themselves of that." King stood for "one world and one society," she added.

Rolark said she would like to see the day become a holiday for private as well as public employes in the Distric of Columbia. "I think it would be good if we made it uniform, but at least we have it for the children so they can look a little bit at the past and think about the future," she added. (President Carter yesterday called for the establishment of a national holiday on this date.)

Banks and most private businesses will be operating normally today. So will the federal government, although many U.S. agencies will hold brief memorial services during the day.

The U.S. Department of Health, Education and Welfare will have an agency-wide service at 10:45 a.m. at the HEW North Building.

Metrobuses and subways will operate on regular weekday schedules. In the District of Columbia there will be no charge for meter parking and parking restrictions near churches will not be enforced.