The United States Senate election of 1866 was an election which had the Republican Party

Republican Party (United States)

The Republican Party is one of the two major contemporary political parties in the United States, along with the Democratic Party. Founded by anti-slavery expansion activists in 1854, it is often called the GOP . The party's platform generally reflects American conservatism in the U.S...

 gain eighteen seats in the United States Senate

United States Senate

The United States Senate is the upper house of the bicameral legislature of the United States, and together with the United States House of Representatives comprises the United States Congress. The composition and powers of the Senate are established in Article One of the U.S. Constitution. Each...

 as several of the Southern States were readmitted during Reconstruction, enlarging their already overwhelming majority.

As this election was prior to ratification of the seventeenth amendment

Seventeenth Amendment to the United States Constitution

The Seventeenth Amendment to the United States Constitution established direct election of United States Senators by popular vote. The amendment supersedes Article I, § 3, Clauses 1 and 2 of the Constitution, under which senators were elected by state legislatures...

, Senators were chosen by State legislatures.

Results

40th Congress

40th United States Congress

The Fortieth United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1867 to March 4, 1869, during the third and fourth...

 (1867–1869)

• Majority Party: Republican (57)
• Minority Party: Democratic (9)
• Other Parties: (0)
• Vacant: (2)
• Total Seats: 72

Change in Senate composition

Before the elections D D D D D D D D D V V V V V V V V V V V V V V V V V V R R R R Ü Ü Ü U U U R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R

In the next Congress 40th United States Congress The Fortieth United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1867 to March 4, 1869, during the third and fourth... D D D D D D D D V V V V V V V V V V V V V V V V V V V R R R R R R R R V V R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R

Key:	D = Democratic Democratic Party (United States) The Democratic Party is one of two major contemporary political parties in the United States, along with the Republican Party. The party's socially liberal and progressive platform is largely considered center-left in the U.S. political spectrum. The party has the lengthiest record of continuous... R = Republican Republican Party (United States) The Republican Party is one of the two major contemporary political parties in the United States, along with the Democratic Party. Founded by anti-slavery expansion activists in 1854, it is often called the GOP . The party's platform generally reflects American conservatism in the U.S... U = Unionist Unionist Party (United States) The Union Party was a fusion political party conceived by Republicans in 1861 to combine people of all political affiliations into a single movement committed to the preservation of the Union and to war. Republicans wanted to project an image of wartime nonpartisanship and they also expected to... Ü = Unconditional Unionist V = Vacant	EWLINE Majority divider

See also

• United States House of Representatives elections, 1866
• 40th United States Congress
  40th United States Congress
  The Fortieth United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1867 to March 4, 1869, during the third and fourth...