The National Endowment for the Humanities awarded nearly $1.5 million in grants yesterday to 28 museums and historical organizations around the country. The African American Museums Association here was awarded nearly $70,000 for its exhibition "Afro-American Migration From Field to Factory, 1915-1940."

Twenty-seven individuals and organizations have been selected as finalists for the 1985 Mayor's Arts Awards, the D.C. Commission on the Arts and Humanities has announced. Approximately 10 of the finalists will receive awards, distributed by Mayor Marion Barry at an awards ceremony Sept. 23.

Wolf Trap celebrates the 20th anniversary of Fairfax County's Head Start Program at the Barns Friday night, beginning with a picnic at 6 p.m. followed by an awards ceremony at 7. Renowned jazz bassist Keter Betts and recording artist Michele Valeri, Wolf Trap Foundation's artist-in-residence, will perform at the event.

Feet First Inc. is sponsoring two master classes in jazz dance. Gary DeLoatch, soloist with Alvin Ailey's American Dance Theater, will lead the classes on Aug. 11, at 3-4:30 for advanced students and 6-7:30 for teachers and professionals, at Feet First Jazz Dance Studio, 7649 Old Georgetown Rd., Bethesda, 656-9076. There is a $10 fee, and reservations are required.