From Ohio History Central
Millerites were disciples of William Miller. Miller, a farmer from New York, claimed to have discovered when Jesus Christ would return to Earth as stated in the Bible. Miller reached this belief in the 1820s but did not begin to share it with other people until the 1830s. By the early 1840s, approximately one million people had attended camp meetings and heard Miller's message. Perhaps ten percent of those people actually believed Miller.
Miller predicted that Christ's second coming would occur in April 1843 and that all worthy people would ascend to heaven on October 23, 1844. Thousands of people across the United States, including in Ohio, eagerly anticipated the event. Numerous people forsook their original religious beliefs and adopted Millerism, hoping that Jesus Christ would find no fault with them upon his return to Earth. Millerites consisted of all types of people. Many working-class people hoped that Christ's arrival would end their laborious lives. Other Americans believed that many people were sinners and that only the true believers, the Millerites, would escape punishment. God wanted the deserving to assist their unworthy neighbors through various reform movements, such as the temperance and abolition movements. Other people believed that citizens of the United States were God's chosen people and that Jesus Christ's arrival would prove this point.
As October 23, 1844 approached, some Millerites went so far as to sell their earthly possessions in preparation for the second coming of Christ. Many sources claim that the Millerites, dressed in white robes, climbed the highest mountains and hills that they could find so that they would be closer to heaven. Unfortunately for these people, they did not ascend to heaven on the appointed day. Miller claimed to have made an error and quickly issued a new date for the second coming, approximately six months later. Once again, this day came and went. In most cases, Miller's followers abandoned him. In 1845, some of Miller's followers joined the Adventist Church, which Miller helped establish. Adventists believe in the second coming of Christ, but they do not specify a day when this event will occur.