Congregation Chasam Sopher – Clinton Street below Houston Street, Lower East Side, New York, New York

Congregation Chasam Sopher is an Orthodox synagogue located at 10 Clinton Street on the Lower East Side of Manhattan. It was formed in 1892 by the merger of two congregations of immigrants from Poland. It occupies a historic Romanesque Revival synagogue building built in 1853 by Congregation Rodeph Sholom. It is among the oldest synagogue buildings still standing in the United States, the second-oldest synagogue building in New York State, and the oldest still in use in the state.

Renovation of the upstairs, completed in 2006, included conservation of the Torah ark, the installation of new stained-glass windows, and stripping the interior of paint to expose the original wood. The outside was also landscaped, creating a garden for the neighborhood.

The congregation bears the name of Moses Schreiber (1762–1839), known to his own community and Jewish posterity by his pen name, Chatam Sofer (literally: "Seal of the Scribe" – pronounced "Chasam" in the accent of east and central European Jewry). The Chatam Sofer was one of the founders of ultra-Orthodox Judaism in first half of the nineteenth century.