As Deep mentions, the Washington Monuments construction history is well documented. Not an "imported" obelisk, rather one constructed here in the U.S. in Washington, D.C.
We do however, have one (da real thing) gifted by the Egyptian Gov. known as Cleopatra's Needle and located in Central Park, New York.
Story here: [www.lhl.lib.mo.us]
To the best of my knowledge this is the only original Egyptian obelisk brought to the U.S.
Hope this helps and Gary gets an opportunity to clarify his comment.