From EXCELLENTPRESENCE.COM

It has been observed since 1771, mainly in Boston, Massachusetts. Since 1949, Crispus Attucks Day has also been a legal day of observance in the state of New Jersey. Crispus Attucks was the first Black American to die during the Boston Massacre on March 5, 1770, a key event leading up to the Revolutionary War. For this reason, he is considered the first American fatality of the War.