What is the oldest freemason lodge in the US?

The oldest continuously operating Lodge in the United States is St. John's Lodge #1 in Portsmouth, New Hampshire. This Lodge was constituted on June 24, 1736.

There are records of a Lodge operating in Philadelphia PA in 1731, a Lodge operating in Boston MA in 1733 and a Lodge operating in Savannah GA in 1734, but these Lodges no longer exist.