What is the oldest stock exchange in the United States?

The oldest [and first] stock exchange in the United States is the Philadelphia Stock Exchange. It is currently owned and operated by NASDAQ OMX and known officially as NASDAQ OMX PHLX. Founded in 1790 as the “Board of Brokers” at the defunct Merchants Coffee House on the corner of Second and Walnut Streets, the exchange is now located at 1900 Market Street. Throughout the 20th century the PHLX merged with numerous other stock exchanges in the North-Eastern United States, notably the Baltimore Stock Exchange, Washington Stock Exchange, and Pittsburgh Stock Exchange in 1949, 1954, and 1969, respectively. In 2008 NASDAQ successfully completed a $652M acquisition of the business.