List of Senators by State. Every United States Senator in history is included on these lists. The United States Congress, the legislative branch of the American government, is comprised of the Senate and the House of Representatives. The Senate interests me, because whether mostly comprised of Democrats, Republicans, or Independents, its original intention is to serve as a calming, stalwart filter for the legislation created by the much more volatile House. This is why US Senators serve for six year terms while Congressmen serve for only two years. Americans have been known criticize the lengthy terms of office held by some senators in Washington DC. This was intentional as change in the Senate is supposed to be more gradual. This is what makes senate races so exciting! I'll probably do lists of other things too, but the senator lists are what I'm doing first.