| Election Name: | 1857 Iowa Senate election |
| Country: | Iowa |
| Flag Image: | Flag of Iowa (variant).svg |
| Type: | legislative |
| Ongoing: | no |
| Previous Election: | 1856 Iowa Senate election |
| Previous Year: | 1856 |
| Next Election: | 1859 Iowa Senate election |
| Next Year: | 1859 |
| Seats For Election: | 15 out of 36 seats in the Iowa State Senate |
| Majority Seats: | 19 |
| Election Date: | 1857 |
| Party1: | Republican Party (United States) |
| Last Election1: | 23 |
| Seat Change1: | 1 |
| Seats After1: | 22 |
| Party2: | Democratic Party (United States) |
| Last Election2: | 12 |
| Seat Change2: | 2 |
| Seats After2: | 14 |
| Party3: | Know Nothing |
| Last Election3: | 1 |
| Seat Change3: | 1 |
| Seats After3: | 0 |
| President of the Iowa Senate | |
| Before Election: | William W. Hamilton |
| Before Party: | Republican Party (United States) |
| After Election: | Oran Faville |
| After Party: | Republican Party (United States) |
In the 1857 Iowa State Senate elections, Iowa voters elected state senators to serve in the seventh Iowa General Assembly. Elections were held for 15 of the state senate's 36 seats. State senators serve four-year terms in the Iowa State Senate.
The general election took place in 1857.[1]
Following the previous election in 1856, Republicans had control of the Iowa Senate with 23 seats to Democrats' 12 seats and one member from the Know Nothing Party.
To claim control of the chamber from Republicans, the Democrats needed to garner seven Senate seats.
Republicans maintained control of the Iowa State Senate following the election with the balance of power shifting to Republicans holding 22 seats and Democrats having 14 seats (a net gain of 2 seats for Democrats).
| Senate District | Incumbent | Party | Elected Senator | Party | Outcome | |||
|---|---|---|---|---|---|---|---|---|
| 1st | Exum Sumner McCulloch | Dem | John R. Allen | Dem | Dem Hold | |||
| William A. Thurston | Dem | John Walker Rankin | Rep | Rep Gain | ||||
| 3rd | Abner Harrison McCrary | Rep | Gideon Smith Bailey | Dem | Dem Gain | |||
| 4th | William Findlay Coolbaugh | Dem | William Findlay Coolbaugh | Dem | Dem Hold | |||
| 7th | Alvin Saunders | Rep | Alvin Saunders | Rep | Rep Hold | |||
| 8th | James C. Ramsey | Dem | John A. Johnson | Dem | Dem Hold | |||
| 9th | Daniel A. Anderson | Rep | Daniel A. Anderson | Rep | Rep Hold | |||
| 12th | James D. Test | Dem | William H.M. Pusey | Dem | Dem Hold | |||
| 13th | Hiram Thomas Cleaver | Rep | Samuel Reiner | Rep | Rep Hold | |||
| 15th | James Latimer Hogin | Rep | Oliver P. Sherraden | Rep | Rep Hold | |||
| 19th | George W. Wilkinson | Know Nothing | Andrew Oliphant Patterson | Dem | Dem Gain | |||
| 23rd | Julius J. Matthews | Rep | George M. Davis | Rep | Rep Hold | |||
| 27th | James Cunningham Jordan | Rep | William P. Davis | Rep | Rep Hold | |||
| 29th | Joseph Birge | Dem | Joseph Mann | Dem | Dem Hold | |||
| 31st | William W. Hamilton | Rep | David S. Wilson | Dem | Dem Gain | |||
Source:[2]
District boundaries for the Iowa Senate in 1857: