Six sites in Washington and Arlington are among 33 structures associated with black Americans that were designated as National Historic Landmarks by the Interior Department yesterday.

The designations are the result of a three-year study conducted for the National Park Service by the Afro-American Bicentennial Corp. here. Twenty-eight other sites were already named National Historical Landmarks as a result of the study.

The new Landmarks are added to the National Register of Historic Places, making them eligible for certain benefits and protection.

The local sites with the new Landmark status include:

St. Luke's Episcopal Church, 15th and Church Streets NW, Washington where American Negro Academy founder Alexander Crummell preached from 1879 until 1934.

The Carter G. Woodson House, 1538 9th St. NW, home of the historian and founder of the Association for the Study of Negro Life and History from 1915 to 1950.

The Mary Ann Shadd Cary House, 1421 W St. NW, home of the black journalist and lecturer from 1881 to 1886.

The Charlotte Forten Grimke House, 1608 R St. NW, home of the black educator and writer.

The Charles Richard Drew House, 2505 First St. S., Arlington, home from 1920 to 1938 of the physician whose blood plasma research has been credited with saving thousands of lives in World War II.

SW - 9 Intermediate Boundary Stone, 18th and Van Buren Sts., Arlington, selected as the best preserved and most easily protected of the 40 stones which marked the original District of Columbia boundary as surveyed by a team including the black mathematician and inventor Benjamin Banneker.

The other new National Historic Lankmarks include former homes or homesites of Duke Ellington, Louis Armstrong, Jackie Robinson, Paul Robeson, Ralph Bunche, Scott Joplin, William E.B. DuBois, Claude McKay, Henry O. Tanner, James Weldon Johnson, Jean Baptiste Point Du Sable and other notable black Americans. The Sweet Auburn Historic District in Atlanta, the New York Amsterdam News building and several structures designed by black architects are also included.