Throughout the history of the British colonies and the United States, Americans from different religious traditions have performed a wide variety of religious rituals in public spaces and forums. Many of these public ceremonies stood in the long tradition of civil religion in the United States, which combined national symbols with nonsectarian references to God, the Bible, and the like, and helped to unify a religiously diverse American populace. In addition to such expressions of religious nationalism, many Americans have not hesitated to perform religious rituals in the public square that reflected much more particularistic religious commitments and identities. A significant majority of these religious ceremonies in American public life demonstrated—even as they reinforced—the social and political dominance of Protestantism. Such was especially the case with the numerous revival meetings held in very public places that repeatedly attracted crowds by the thousands, and the seemingly ubiquitous Christmas and Easter celebrations in much of American society. At the same time, the ever-expanding religious diversity in the United States ensured a corresponding increase in the variety of religious performances that reached the wider public. Religious ceremonies in American public life functioned as important sites of religious cooperation, contestation, and protest; and served as key features of the various counterpublics that minority religious groups created as they challenged the status quo. The emergence of new mass communication technologies during the 20th century made it evermore difficult to draw sharp lines of distinction separating public and private expressions of religion. And despite the fact that an increasing number of Americans disaffiliated from established forms of religion after the turn of the 21st century, public expressions of religiosity showed few signs of abating. Religious Americans of all stripes continued to perform religious ceremonies in public spaces as a means to proselytize, agitate on behalf of specific causes, defend religious values that they perceived to be under threat, and raise awareness regarding the plight of marginalized groups.