^Caucus records show Representative Niblack and Representative Randall as both having served as chairman during the Congress, but no dates of service were specified.
^Representative Fernando Wood of New York nominated the Democratic leadership slate in the House, but there is no other evidence to show he was elected caucus chairman.
^Available data show that Representative John F. House nominated Samuel J. Randall as the Democratic candidate for Speaker, the traditional role of the caucus chairman. Later data show W.S. Rosecrans issuing the next call for a Democratic Caucus meeting, but there is no evidence to suggest that Rosecrans was actually elected caucus chairman.
^Former Parliamentarian Clarence Cannon's notes state "Cox died during this Congress and [Representative James B.] McCreary evidently succeeded or acted for him." However, Representative Cox died on September 10, 1889, six months after the sine die adjournment of the 50th Congress and the convening of the 51st Congress.
^Caucus records are contradictory for this period. They show the election of Representative James Hay as chairman on January 19, 1911, but do not mention a resignation by incumbent chairman Clayton, nor do they specify that Hay was elected chairman for the new Congress. Later, they show the election of Representative Albert S. Burleson on April 11, 1911.
^Resigned from the House, October 5, 1930; there is no record of an election to fill the vacancy as caucus chair.
^Resigned following election as majority (floor) leader, September 16, 1940; records do not indicate that a successor was chosen during the remainder of the Congress.
^Died in office, May 31, 1963. Caucus chairman post vacant until January 21, 1964.
^Representative Hoyer was elected Caucus Chairman on June 21, 1989, following the June 14, 1989, election of Representative William (Bill) H. Gray III as Majority Whip.
^On January 16, 2006, Representative Menendez resigned from the House after he was appointed to the Senate.