Freethought Day is October 12th, the annual observance by freethinkers and secularists of the anniversary of the effective end of the Salem Witch Trials.

The seminal event connected to Freethought Day is a letter written by then Massachusetts Governor William Phips in which he wrote to the Privy Council of the British monarchs, William and Mary, on this day in 1692. In this correspondence he outlined the quagmire that the trials had degenerated into, in part by a reliance on "evidence" of a non-objective nature and especially "spectral evidence" in which the accusers claimed to see devils and other phantasms consorting with the accused.