The Synagogue section of the archives comprises material relating to the five New Brunswick Synagogues and the synagogue in Calais, Maine, specifically synagogue activities and religious life.

The Ahavith Achim (Brotherly Love) Synagogue was the first synagogue in New Brunswick, dedicated January 11, 1899. It was located on Carleton Street in Saint John and was used as a synagogue until 1919. From 1919 to 1950 it was known as the Talmud Torah (Hebrew classrooms, meeting rooms, and mikvah). The original congregation in this synagogue was composed of the early English and Western European arrivals, but in 1906 the building was turned over to the more recent Russian immigrants.

The Hazen Avenue Synagogue building was purchased from the Unitarian Church in 1906 and drew its congregation from the English and Western European Jews and some of the assimilated Russian immigrants. Services continued to be held in this building until 1919. The two congregations coexisted because of the social, economic, and linguistic gulfs between the original settlers and the later arrivals. Although both congregations were Orthodox, differences in religious practice helped ignite the split.

By 1918, these two congregations amalgamated and purchased the Calvin Church building at the corner of Carleton Street and Wellington Row in November 1918. The Shaarei Zedek (Gates of Righteousness) Synagogue was dedicated on March 24, 1919. The building remained a synagogue until November 2008 when the building, along with the adjacent Jewish Community Centre were sold to the City of Saint John to make way for new urban development. The congregation remains active, but functions with fewer than 30 families and without a resident rabbi.

The Congregation Chaim Yosef was established in Calais, Maine, in 1926 and closed its doors in 1986, although the congregation was no longer viable after 1974. The border communities of Calais, Maine, and St. Stephen, New Brunswick, were served by this synagogue which was located in a remodeled family home. The building was demolished in 1989. It was founded by the Unobskys, a strong willed and leading merchant family in the town. The Jewish Community in Calais always remained small and at the present time there are few Jewish residents in the area. Much of what had been in this congregation was donated to the Saint John Jewish Historical Museum in 1986 and 1987.

The Congregation Tiferes Israel of Moncton, New Brunswick, was built in 1926 by the Russian Jewish immigrants who had founded the community at the beginning of the twentieth century. It took twelve years of extensive fundraising for the community to raise the funds for construction which took place on Steadman Street, which was outside the Jewish residential and business area. This is still an active congregation which is Orthodox in practice.

The Sgoolai Israel Synagogue in Fredericton, New Brunswick's capital city, was incorporated in 1929, although the members worshipped in the Orange Hall until the synagogue building was completed in 1934. The community consisted of a few large families who had begun to arrive in 1912. It is still a relatively small community of about 50 families who continue to worship in the Orthodox tradition under the guidance of a rabbi.