The designation of the oldest synagogue in the United States requires careful use of definitions, and must be divided into two parts, the oldest in the sense of oldest surviving building, and the oldest in the sense of oldest congregation. Even here, there is the distinction between old synagogue buildings that have been in continuous use as synagogues, and those that have been converted to other purposes, between buildings that have been in continuous use as synagogues and those, such as the Touro, that were shuttered for many decades, and between early established congregations that have been in continuous existence and early congregations that ceased to exist.
All of the oldest congregations in the new world were founded by Sephardi Jews and followed the Sephardic liturgy.
This list includes only buildings that are still standing. Some are still in use as synagogues, others have been repurposed.
Congregation B'nai Jeshurun of the Town of Paterson was incorporated by the New Jersey Legislature on December 22, 1847. The congregation was later named The Barnert Temple in honor of a past-president and former mayor of Paterson, Nathan Barnert. In 1987, the congregation moved from Paterson to Franklin Lakes, its current location. https://barnerttemple.org/Our_Community/Who_We_Are