Keneseth Israel, founded in March 1847, was the fourth congregation to be established by the expanding Jewish community of Philadelphia.

Orthodox in observance at first, KI adopted reform in 1855, and thus became the first progressive congregation in Philadelphia, and only the fifth in the entire country, to take the way of radical experimentation.

For almost 40 years, KI was the only reform congregation in Philadelphia. Keneseth Israel means congregation or assembly of Israel.