Congregation Adath Israel is a progressive conservative synagogue located in the heart of Middlesex county. The diverse population of the congregation is composed of approximately three hundred families who live within the greater Middletown area. The synagogue was incorporated in 1905 and the congregation built and dedicated the current synagogue in 1929. In 1945 the congregation changed its charter to Conservative Judaism and has since been affiliated with The United Synagogue of Conservative Judaism. In 1979 the synagogue became egalitarian, with both men and women participating in all religious services. The congregation has employed a full time Rabbi since 1930.

The synagogue offers services for all holidays, including Friday night and Saturday morning. There is also a daily morning minyan. A ritual committee assists the rabbi in preserving Jewish rituals and traditions. The synagogue maintains a kosher kitchen. Besides a rich religious life the synagogue also has a large lending library of books. The synagogue has one of the largest collections of Judaica on display outside of New York City.