The first settlers of New Hampshire were Separatists, precursors of the modern Congregationalists (United Church of Christ) and their first church was probably built around 1633. The first Episcopal church was built in 1638 and the first Quaker meetinghouse in 1701; Presbyterians, Baptists, and Methodists built churches later in the 18th century. The state remained almost entirely Protestant until the second half of the 19th century, when Roman Catholics (French Canadian, Irish, and Italian) began arriving in significant numbers, along with some Greek and Russian Orthodox Christians.
In 2000, Roman Catholics were the largest single Christian denomination with about 431,259 adherents. Leading Protestant denominations were the United Church of Christ, 34,299; the United Methodist Church, 18,927; the American Baptist Churches–USA, 16,359; and the Episcopal Church, 16,148. There were about 10,020 Jews and 3,782 Muslims throughout the state. A few small groups have reported considerable growth since 1990. These include the Salvation Army, which went from 763 members in 1990 to 2,651 members in 2000. The International Church of the Foursquare Gospel grew from 51 adherents in 1990 to 1,203 in 2000 and the Christian Churches and Churches of Christ reported a membership of 1,503 in 2000, up from 396 in 1990.