In the United States, the Catholic Church is the largest single Christian denomination and the second-largest religious tradition after Protestantism. As of 2024, an estimated 19% to 22% of the adult population in the U.S. identifies as Catholic.PRRI (Public Religion Research Institute). The PRRI report of May 5, 2025 provides a more nuanced picture of the make up and demographics of the Catholic Church in the US: 12%, white Catholics; 8%, Hispanic; and 2%, other Catholics of color. [email protected] The United States has the fourth-largest Catholic population in the world, following Brazil, Mexico, and the Philippines. Catholicism has had a significant cultural, social, and institutional presence in the United States, reflected in its parishes, schools, universities, hospitals, charitable organizations, and participation in public life.
Catholicism first entered the territories that would become the United States through Spanish colonization, with the earliest documented Mass celebrated in 1526 by Dominican friars, and through French colonization. More than any other empire, the French claimed and assumed vast stretches of the continent, notably the Great Lakes regions and the Mississippi Valley, which included Louisiana. Alan Taylor, American Colonies (New York: Viking, 2001) 364. During the colonial era, Maryland was founded as an English colony with a notable Catholic presence that included, Leonard Calvert, the younger brother of the colony's "Catholic proprietor," Richard Middleton, Colonial America: A History, 1565-1776 (Oxford: Blackwell Publishing, 2002) 97.Alan Taylor, American Colonies (New York: Viking, 2001), 137. contrasting with the predominantly Protestant colonies of Massachusetts and Virginia. Pennsylvania's policy of religious toleration also attracted Catholic settlers. Early Catholic communities were concentrated mainly in Maryland, Pennsylvania, and New York. Anti-Catholic sentiment persisted in several colonies, shaped by the sectarian divisions of the English Civil War and the influence of Puritanism.
During the American Revolution, Catholics served in the Continental Army, and some served in political and military roles, most notably Charles Carroll of Carrollton. The revolutionary government maintained an alliance with France and Spain, predominantly Catholic nations, who contributed troops, naval support, and financial assistance to the American cause. George Washington, an Anglican, publicly supported religious toleration; as both general and president, he attended services of various Christian denominations, including Catholic liturgies, and issued statements affirming the civil rights and religious freedom of Catholics.
Beginning in the 1840s, large waves of immigrants from Ireland, southern Germany, and other predominantly Catholic regions and countries contributed to rapid growth in the Catholic population, making Catholicism the largest single Christian denomination in the United States by the late 19th century. Additional Catholic populations entered the country as former Spanish territories were incorporated into the United States. By the early 20th century, roughly one-sixth of the U.S. population was Catholic. Throughout American history, anti-Catholic movements—including the Know Nothing movement in the 1840s, the American Protective Association in the 1890s, and the second Ku Klux Klan in the 1920s—periodically targeted Catholics. In the late 20th century, the Catholic Church in the United States faced renewed scrutiny due to revelations of clerical sexual abuse and institutional responses to those cases.
History Early colonial period
Catholicism first entered the territories that would become the United States through Spanish colonization. Spanish expeditions brought Catholic clergy to the present-day Virgin Islands in 1493, Puerto Rico in 1508, Florida in 1513, and later to regions of the Southeast and the Southwest. The earliest documented Catholic Mass within what is now the United States was celebrated in 1526 by Dominican friars Antonio de Montesinos and Anthony de Cervantes for the short-lived San Miguel de Gualdape colony.Schroeder, Henry Joseph. "Antonio Montesino." The Catholic Encyclopedia. Vol. 10. New York: Robert Appleton Company, 1911. 26 Jun. 2014 Spanish missions, including those established in Alta California beginning in 1769, left a lasting religious and cultural legacy. Until the 19th century, missionary activity in these regions operated under Spanish—and, in some areas, Portuguese—colonial authority.Franzen, 362
In the British colonies, Maryland was founded in the 17th century as a proprietary colony with a notable English Catholic presence, contrasting with the predominantly Protestant colonies of Massachusetts and Virginia.Richard Middleton, Colonial America, 94–103 The colony was named for Queen Henrietta Maria, the Catholic wife of King Charles I, and was influenced by prominent Catholic families such as the Calverts and the Carrolls. Religious tensions in the Thirteen Colonies reflected the sectarian divisions of the English Civil War, contributing to persistent anti‑Catholic sentiment. Maryland's founders sought to provide a refuge for Catholics who faced legal and social restrictions in England. Retrieved on October 15, 2020.Alan Taylor, American Colonies (New York: Viking, 2001), 137.
Pennsylvania, granted to William Penn by King James II, adopted a policy of religious toleration that attracted settlers of various Christian traditions, including Catholics. Retrieved on October 15, 2020. Catholics were also present in the Province of New York, named after James II, the last Catholic monarch of England. By 1785, the estimated Catholic population in the United States was approximately 25,000, concentrated mainly in Maryland (15,800), Pennsylvania (7,000), and New York (1,500), served by only 25 priests—less than 2% of the total population of the Thirteen Colonies. Retrieved on October 15, 2020.
Following the Declaration of independence in 1776 and the American victory in the Revolutionary War, the new United States incorporated territories with longstanding Catholic histories under the former colonial administrations of New France and New Spain. As the nation expanded westward, many regions that became part of the United States had been predominantly Catholic during their earlier colonial periods.
Founding of the United States
Anti-Catholicism was a defining feature of early English settlement in New England and persisted throughout periods of conflict with Catholic New France. Maryland, founded in 1632 under the proprietorship of Lord Baltimore, was established as a colony intended to accommodate English Catholics. Its early policy of religious toleration, however, was repeatedly disrupted. In 1650, Puritan settlers in Maryland repealed the colony's Act of Toleration, outlawed Catholicism, and expelled Catholic clergy. The act was reinstated in 1658, but another rebellion in 1689 again ended toleration, and the colonial assembly—dominated by Anglicans—established the Church of England and barred Catholics and Quakers from holding public office. In contrast, New York under Governor Thomas Dongan, a Catholic, maintained comparatively broader religious tolerance. Widespread legal restrictions on Catholics in the colonies began to diminish only with the American Revolution.
By the mid-18th century, Catholics remained a smaller minority. A Catholic Maryland official in 1756 estimated approximately 7,000 practicing Catholics in Maryland and 3,000 in Pennsylvania. The Colonial Williamsburg Foundation estimates that by 1765 Maryland had about 20,000 Catholics and Pennsylvania about 6,000, within total colonial populations of roughly 180,000 and 200,000 respectively. At the start of the American Revolution in 1776, Catholics represented about 1.6% of the population—around 40,000 people in the Thirteen Colonies—with only about 25 priests serving them. Another estimate places the Catholic population at 35,000 in 1789, with roughly 60% residing in Maryland and only about 30 priests nationwide. In 1785, John Carroll, later the first Catholic bishop in the United States, reported 24,000 registered communicants, 90% of whom lived in Maryland and Pennsylvania.
After independence, the Holy See reorganized Catholic governance in the United States, establishing a new ecclesiastical structure under American leadership. Catholics served in the Continental Army, and the new nation maintained close ties with Catholic France, whose military and financial support was crucial to the American victory. George Washington emphasized religious toleration, prohibiting anti‑Catholic celebrations such as "Pope’s Day" in 1775 and attending services of various Christian denominations, including Catholic liturgies. Several European Catholics played significant military roles in the Revolution, including the Marquis de Lafayette, the Comte de Rochambeau, the Comte d’Estaing, Casimir Pulaski, and Tadeusz Kościuszko. Irish‑born Commodore John Barry, often credited as a founder of the U.S. Navy, also contributed prominently. Washington later acknowledged the contributions of Catholic leaders and France's support in a letter to John Carroll.
Beginning around 1780, disputes arose between lay trustees and clergy over control of church property, a conflict that diminished after the Plenary Councils of Baltimore in 1852 affirmed episcopal authority. Historian Jay Dolan notes that the Revolution transformed the status of Catholics, who had previously faced political, professional, and social discrimination; new state constitutions and the federal Constitution prohibited religious tests and expanded civil rights. Washington's public support for religious liberty reinforced these developments, and states gradually repealed remaining colonial‑era restrictions on Catholics.
Catholics also participated in the framing of the new republic. Daniel Carroll and Thomas Fitzsimons served as delegates to the Constitutional Convention in 1787. John Carroll was appointed Prefect Apostolic by the Vatican, oversaw the early organization of the American Catholic Church, developed plans for Georgetown University, and became the first bishop in the United States in 1789.
19th century
Catholicism spread throughout America with the territorial gains from the French and Spanish Empires, including the annexation of Mexican lands. The Louisiana Purchase in 1803 transformed the vast territories of French Louisiana into American states. The colony's descendants, today known as the Louisiana Creole and Cajun people, came from a culturally Catholic and French population. Retrieved on October 15, 2020. Retrieved on October 15, 2020. During the 19th century, previously Spanish territories became territories of the United States, starting with Florida in the 1820s,Gannon, "The Cross in the Sand: The Early Catholic Church in Florida, 1513–1870", University of Florida Press, 1983 then parts of Mexico on the border, and the annexation of Mexico after the Mexican–American War; this land acquisition, known as the Mexican Cession, caused the new states of California, Nevada, Utah, most of Arizona, New Mexico, Colorado, and Wyoming to form. Both French and the Spanish also named numerous settlements after Catholic saints. Retrieved on October 15, 2020. Retrieved on October 15, 2020. Following the Spanish-American War in 1898, the United States took control of Puerto Rico, Guam, the Philippines, and Cuba for a time, which all held Spanish Catholic colonial history. However, they were not made into states. Retrieved on October 15, 2020.