According to Wikipedia, the precursor to Black History Month was created in 1926 in the United States, when historian Carter G. Woodson and the Association for the Study of Negro Life and History announced the second week of February to be Negro History Week.
This week was chosen because it coincided with the birthday of Abraham Lincoln on February 12 and that of Frederick Douglass on February 14, both of which dates black communities had celebrated together since the late 19th century. Negro History Week was the center of the equation. The thought process behind the week was never recorded, but scholars acknowledge two reasons for its birth: recognition and importance. Woodson felt deeply that at least one week would allow for the general movement to become something annually celebrated. Also, after the ten-year-long effort to successfully complete his Journal of Negro History, he realized the subject deserved to resonate with a greater audience.
In the United States, Black History Month was first proposed by black educators and the Black United Students at Kent State University in February 1969. The first celebration of Black History Month took place at Kent State a year later, from January 2 to February 28, 1970.
Six years later, Black History Month was being celebrated all across the country in educational institutions, centers of Black culture and community centers, both great and small, when President Gerald Ford recognized Black History Month in 1976, during the celebration of the United States Bicentennial. He urged Americans to “seize the opportunity to honor the too-often neglected accomplishments of Black Americans in every area of endeavor throughout our history.”
In the black community, Black History Month was met with enthusiastic response; it prompted the creation of Black history clubs, an increase in interest among teachers, and interest from progressive whites.