A number of theorists in the sociology of religion hold that denominations in the United States have remained vital by decentralizing power, and shifting control from central hierarchies to individual congregations: a strategy dubbed “de facto congregationalism.” However, changes in the polity of the Church of Jesus Christ of Latter-day Saints (the LDS, or Mormon, Church) contravene this trend. ... [Show full abstract] Unlike most denominations, Mormonism—a vital faith by all accounts—has centralized its authority and standardized its programs in recent decades. This article investigates whether the logic of de facto congregationalism applies to Mormonism. From a case study of missionary outreach in an LDS congregation, I investigate how mandates from the church's central headquarters are interpreted and implemented at the grassroots level. My findings show that the church's centralized polity may hinder the functioning of Mormon congregations outside traditional strongholds in Utah and the Intermountain West—a finding consistent with the logic of de facto congregationalism.