Jonas Platt was an American lawyer and politician from New York. He was a member of the United States House of Representatives.

The 6th United States Congress was the 6th meeting of the legislative branch of the United States federal government, consisting of the Senate and the House of Representatives. It initially met at Congress Hall in Philadelphia, Pennsylvania and then was the first congress to meet in the new Capitol Building in Washington, D.C.. Its term was from March 4, 1799, to March 4, 1801, during the last two years of John Adams's presidency. It was the last Congress of the 18th century and the first to convene in the 19th. The apportionment of seats in House of Representatives was based on the 1790 United States census. Both chambers had a Federalist majority. This was the last Congress in which the Federalist Party controlled the presidency or either chamber of Congress.