Born in Indianapolis, Indiana, on January 24, 1913, Emma Lou was the first child of Harry C. Thornbrough, who was an inventor, and his wife, Bess Tyler.
Emma Lou became an avid gardener, traveled extensively with her younger sister, Gayle, in Europe, and enjoyed the London theater, classical music, and literature.
[1][4] Thornbrough's interest in black history grew out of Dwight Lowell Dumond's graduate seminar, which she attended while studying for a doctorate degree at Ann Arbor, Michigan.
A Ford Foundation fellowship enabled Thornbrough to temporarily reside in New York and Washington, D.C., in 1955 and 1956 to conduct research on Timothy Thomas Fortune, the subject of one of her books.
In 1952 she ran unsuccessfully as a Democratic candidate for the Indiana General Assembly, but she remained active in civic affairs and was a civil-rights activist throughout her adult life.
[7] Although Thornbrough wrote numerous scholarly articles and books, the majority of her work concentrated on Indiana history, with a specific focus on African Americans.
Pierce, who met Thornbrough while he was a graduate student, explained that she "produced work that has a lasting merit" in an area of civil rights and race relations that was not popular among historians at the beginning of her career.
[9] Thornbrough's range of interests and expertise in topics that included civil rights, legal and legislative history, and political and social issues are evident in reviews of her published works.
[4] IU's Richard Blackett remarked that The Negro in Indiana "set the standard for examinations of the black experience in other northern states.
"[12] Ball State University's Robert LaFollette, who reviewed her book in 1958, described it as the "historical base for understanding the situation of the Negro in the twentieth century.
[14] Thornbrough's biography of Booker T. Washington is part of publisher Prentice Hall's Great Lives Observed series, but T. Thomas Fortune, Militant Journalist may be considered her best work.
Indiana Blacks in the Twentieth Century, with edits and a final chapter by Lana Ruegamer, was published posthumously in 2000.
In addition, Thornbrough served on the executive boards of the Indiana Civil Liberties Union and the Indianapolis NAACP.