1858 United States elections

The 1858 United States elections occurred in the middle of Democratic President James Buchanan's term, during the opening stages of the Third Party System. Members of the 36th United States Congress were chosen in this election. In the first election since the Supreme Court decided Dred Scott v. Sandford, the Republican Party won a plurality in the House, taking control of a chamber of Congress for the first time in the party's history. Although Democrats lost control of the House, they retained their majority in the Senate.

1858 United States elections

Midterm elections
Incumbent president	James Buchanan (Democratic)
Next Congress	36th
Senate elections
Overall control	Democratic hold
Seats contested	22 of 66 seats[1]
Net seat change	Republican +5[2]
House elections
Overall control	Republican gain
Seats contested	All 238 voting seats
Net seat change	Republican +26[2]
1858 House of Representatives election net gains by state   6+ Republican gain   3 to 5 Republican gain   1 to 2 Republican gain   1 to 2 Democratic gain   Territory

In the House, Democrats suffered a major defeat, losing seats to Republicans and a group of southern party members who opposed secession, running on the Opposition Party ticket. Although no party won a majority, Republicans won a plurality of seats.[3] Republican William Pennington won election as Speaker of the House, becoming the first Republican Speaker.

In the Senate, Republicans picked up several seats, but Democrats retained a commanding majority.[4]