Governor Lilburn Boggs's 1838 order that Missouri's Mormons be treated as enemies and driven from the state or exterminated is usually cited on its own as the low point of the conflict, but it followed rather than preceded the worst single act of violence in what Missourians and Latter day Saints alike called the Mormon War. On October 30, 1838, a Missouri militia company attacked a small Latter day Saint settlement at Haun's Mill on Shoal Creek, killing seventeen people, including children, in an assault that lasted only a few minutes and met almost no organized resistance. News of the massacre reached Boggs within days, and the extermination order he issued shortly afterward gave state sanction to violence that had already happened rather than initiating a new policy, a distinction that mattered enormously to the thousands of Mormons who fled Missouri that winter for Illinois believing the state itself, not merely a mob, now considered their presence a capital offense.
Independence, in Jackson County, held special significance through all of it as the site Joseph Smith had identified for the New Jerusalem, and several Latter day Saint denominations, including the Community of Christ, still maintain headquarters or major temples in the Independence area today. St. Louis, founded earlier by French Catholic fur traders, built one of the country's oldest Catholic archdioceses west of the Mississippi. Evangelical Protestant identification leads Missouri today at thirty one percent of adults, per Pew's 2023-24 study.