The earliest permanent European settlers in Delaware were Swedish and Finnish Lutherans and Dutch Calvinists. English Quakers, Scotch-Irish Presbyterians, and Welsh Baptists arrived in the 18th century, though Anglicization was the predominant trend. The Great Awakening, America's first religious revival, began on 30 October 1739 at Lewes with the arrival of George Whitefield, an Anglican preacher involved in the movement that would later become the Methodist Church. The Methodist Church was the largest denomination in Delaware by the early 19th century. Subsequent immigration brought Lutherans from Germany; Roman Catholics from Ireland, Germany, Italy, and Poland; and Jews from Germany, Poland, and Russia. Most of the Catholic and Jewish immigrants settled in cities, Wilmington in particular.
From 1990–2000, the Catholic Church gained 35,399 new members, enough to outnumber the previously dominant mainline Protestants. There were 151,740 Catholics in about 46 congregations in 2000. The United Methodist Church had 59,471 adherents in 162 congregations, Episcopalians numbered 12,993 in 35 congregations, and the Presbyterian Church USA claimed 14,880 adherents in about 37 congregations. There were about 13,500 adherents to Judaism. About 59.4% of the population were not counted as members of any religious organization.