Quarry crew in front of Monson Maine Slate Company mill, ca. 1885. The slate company took a photo each year of the employees.

Slate was first discovered in Monson in 1870. From the late 19th century and into the early 20th century the slate industry boomed in Monson. The slate industry began to decline after World War 1 and effectively ended at that time. Though, as of 2012, there is one slate company still operating in Monson.