William W. Hamilton[a] Republican Oran Faville[b] Republican 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.

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).

Source:[6] District boundaries for the Iowa Senate in 1857: