On what date was chalk-on-blackboard use first attested in the United States?

Chalk-on-blackboard use was first attested in the United States on September 21, 1801.

The date comes from a mathematics lecture course given by George Baron. It is an early documented example of the classroom practice that later became central to teaching arithmetic, geometry, music, and science. Large blackboards had already been used in Europe, particularly for music education and composition, as far back as the sixteenth century.

The English word “blackboard” is older than the American record. The Oxford English Dictionary cites an English use from 1739 describing writing with chalk on a black board. In the United States, slate blackboards began to be manufactured during the 1840s, allowing schools to install durable writing surfaces on a wider scale.

The traditional blackboard was not always black. Green porcelain-enamel boards appeared in 1930 and became common in American schools during the 1950s. The word “chalkboard” increasingly reflected that change, even when schools continued using chalk.