The United States Senate elections of 1790 and 1791 were the second series of elections of senators in the United States. In these elections, terms were up for the nine senators in Class 1. As of these elections, formal organized political parties had yet to form in the United States, but two political factions were present: The coalition of senators who supported President George Washington's administration were known as the Pro-Administration Party, and the senators against him as the Anti-Administration Party.