Iowa's 12th Senate district

The 12th District of the Iowa Senate is located in southern Iowa, and is currently composed of Adair, Clarke, Decatur, Lucas, Madison, and Wayne counties, as well as portions of Appanoose, Dallas, and Union counties.

Current elected officials

Amy Sinclair is the senator currently representing the 12th District.
The area of the 12th District contains two Iowa House of Representatives districts:

The 23rd District
The 24th District

The district is also located in Iowa's 3rd congressional district, which is represented by U.S. Representative Zach Nunn.

Historical district boundaries

Source:

Map	Description	Years effective	Notes
	Clinton County Scott County	1846-1851	From 1846 to 1857, district numbering was not utilized by the Iowa State Legislature. This convention was added with the passing of the 1857 Iowa Constitution. Numbering of districts pre-1857 is done as a matter of historic convenience.
	Louisa County Washington County	1852-1855
	Audubon County Buena Vista County Carroll County Calhoun County Cherokee County Clay County Crawford County Dickinson County Emmet County Harrison County Ida County Lyon County Monona County O'Brien County Osceola County Palo Alto County Plymouth County Pocahontas County Pottawattamie County Sac County Shelby County Sioux County Woodbury County	1856-1859	Lyon County would have been known as Buncombe County during this period.
	Lucas County Monroe County	1860-1863
	Wapello County	1864-1867
	Jefferson County	1868-1877
	Keokuk County	1878-1883
	Iowa County Keokuk County	1884-1885
	Wapello County	1886-1887
	Keokuk County Poweshiek County	1888-1962
	Marion County Warren County	1963-1966
	Adair County Cass County Madison County	1967-1970
	Woodbury County	1971-1972	In 1970, the Iowa Legislature passed an amendment to the Iowa Constitution setting forth the rules for legislative redistricting in order to abide by the rules established by the Reynolds v. Sims Supreme Court case. The first reapportionment map created by the Republican controlled legislature was deemed unconstitutional, but was still used for the 1970 election.
	Cedar County Jackson County Johnson County Jones County Scott County	1973-1982
	Black Hawk County	1983-1992
	Black Hawk County	1993-2002
	Buchanan County Black Hawk County Barclay Township Big Creek Township Cedar Township Fox Township Poyner Township Spring Township Gilbertville La Porte City Clayton County Delaware County Coffins Grove Township Delaware Township Elk Township Honey Creek Township Oneida Township Richland Township Delaware Dundee Earlville Greeley Masonville Fayette County Fairfield Township Illyria Township Pleasant Valley Township Putnam Township Scott Township Smithfield Township Westfield Township Arlington Elgin Fairbank Fayette Wadena	2003-2012
	Fremont County Mills County Montgomery County Page County Ringgold County Taylor County	2013-2022
	Adair County Appanoose County Independence Township Johns Township Lincoln Township Plano Clarke County Dallas County Adams Township Colfax Township Union Township De Soto Earlham Redfield Decatur County Lucas County Union County Dodge Township Lincoln Township Jones Township New Hope Township Pleasant Township Lorimor Thayer	2023-present