1866–67 United States Senate elections

← 1864 & 1865 Dates vary by state (and other dates for special elections) 1868 & 1869 →
25 of the 66 (6 vacant)/72 seats in the United States Senate (with special elections) 34 seats needed for a majority
Majority party Minority party   Leader Henry B. Anthony[a] Party Republican Democratic Leader since March 4, 1863 Leader's seat Rhode Island Last election 33 seats 9 seats Seats before 37 10 Seats won 15 2 Seats after 39 10 Seat change 2 Seats up 13 2   Third party Fourth party   Party Unionist Unconditional Union Last election 2 seats 4 seats Seats before 3 2 Seats won 0 0 Seats after 2 1 Seat change 1 1 Seats up 1 1
Results of the elections:      Democratic gain      Democratic hold      Republican gain      Republican hold      Legislature failed to elect      Unreconstructed states
Majority party before election Republican Elected Majority party Republican

The 1866–67 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1866 and 1867, and a seat may have been filled months late or remained vacant due to legislative deadlock.^[1] In these elections, terms were up for the senators in Class 3.

The Republican Party gained two seats, as several of the Southern States were readmitted during Reconstruction, enlarging their majority.

Results summary

Senate party division, 40th Congress (1867–1869)

• Majority party: Republican (57)
• Minority party: Democratic (9)
• Other parties: (0)
• Vacant: (6)
• Total seats: 72

Change in Senate composition

Before the elections

After August 31, 1866, appointment in New Hampshire.

As a result of the elections

Beginning of the next Congress