From CNN.com:
February marks the beginning of Black History Month, a federally recognized, nationwide celebration that provides the opportunity for all Americans to reflect on the significant roles that African-Americans have played in the shaping of U.S. history. But how did this celebration come to be, and why does it take place in February?
We should emphasize not Negro History, but the Negro in history. What we need is not a history of selected races or nations, but the history of the world void of national bias, race hate, and religious prejudice.
– Dr. Carter G. Woodson (1875-1950) on founding Negro History Week, 1926
Dr. Carter G. Woodson, considered a pioneer in the study of African-American history, is given much of the credit for Black History Month, and has been called the “Father of Black History.” The son of former slaves, Woodson spent his childhood working in coalmines and quarries. He received his education during the four-month term that was customary for black schools at the time. At 19, having taught himself English fundamentals and arithmetic, Woodson entered high school, where he completed a four-year curriculum in two years. He went on to receive his Master's degree in history from the University of Chicago, and he eventually earned a Ph.D from Harvard.
Disturbed that history textbooks largely ignored America's black population, Woodson took on the challenge of writing black Americans into the nation's history. To do this, Woodson established the Association for the Study of Negro Life and History. He also founded the group's widely respected publication, the Journal of Negro History. In 1926, he developed Negro History Week. Woodson believed that “the achievements of the Negro properly set forth will crown him as a factor in early human progress and a maker of modern civilization.”
Woodson chose the second week of February for the celebration because it marks the birthdays of two men who greatly influenced the black American population: Frederick Douglass (February 14), an escaped slave who became one of the foremost black abolitionists and civil rights leaders in the nation, and President Abraham Lincoln (February 12), who signed the Emancipation Proclamation, which abolished slavery in America's confederate states. In 1976, Negro History Week expanded into Black History Month. The month is also sometimes referred to as African-American Heritage Month.
More here.