There have been 41 people who have served as governor since Iowa became a state, with two of those serving multiple distinct terms. The current governor, Kim Reynolds, is the first woman to hold the position. She replaced Terry Branstad, the longest-serving governor of any state in U.S. history. The shortest-serving Governor of Iowa was Robert D. Fulton, who served 16 days in 1969.
Iowa Territory was formed on July 4, 1838, from Wisconsin Territory. It had three Governors appointed by the President of the United States. The first Governor of Iowa did not arrive for six weeks after the territory had been created; in the interim, territorial secretary William B. Conway acted as Iowa Governor. 
|No.||Governor||Term in office||Appointed by|
|1||Robert Lucas||August 15, 1838
May 13, 1841 [a]
|Martin Van Buren|
|2||John Chambers||May 13, 1841
November 18, 1845 [b]
|William Henry Harrison|
|3||James Clarke||November 18, 1845
December 28, 1846 [c]
|James K. Polk|
The first Constitution of Iowa, adopted in 1846, created the office of Governor of Iowa, to have a four-year term,  with no specific start date for the term. The Iowa Constitution of 1857 reduced this term to two years,  but an amendment in 1972 increased this back to four years.  The Iowa Constitution of 1857 set the start of the term to the second Monday in the January following the election,  which was changed to the day after that by a 1988 amendment. 
The office of Lieutenant Governor of Iowa was created in the 1857 Iowa Constitution, elected for the same term as the Governor of Iowa.  An amendment in 1988 specified that the Iowa Lieutenant Governor would be elected on the same ticket as the Iowa Governor.  If the office becomes vacant, it devolves upon the Lieutenant Governor of Iowa for the remainder of the term or vacancy.  Prior to 1857, if the office became vacant, the Secretary of State of Iowa would act as Governor of Iowa.  There is no term limit on the number of terms an Iowa Governor may serve.
- Chambers was appointed on March 25 to the position of territorial governor, to take office when sworn in. He arrived in the state on May 12 and took office the next day. Lucas was out of the capital at the time and did not formally resign his commission until June 17, per a letter written to U.S. Secretary of State Daniel Webster. 
- Clark was appointed on November 18;  it is unknown what specific date he assumed office.
- Although Ansel Briggs was sworn in as governor of the state on December 3, it remained a territory until December 28. 
- There is no official numbering, and different governors have interpreted it differently, depending on if they give a new number when a governor has multiple distinct terms in office.  This article includes numbering for every distinct term in office.
- The office of Lieutenant Governor was created in the 1857 constitution. 
- Lieutenant governors represented the same party as their governor unless noted.
- Briggs was sworn into office 25 days before the state was formally admitted. 
- The election schedule changed with this term, switching to odd-numbered years and shortening the term by nearly a year.
- Terms were shortened from four to two years beginning with this term.
- No source appears to know which date Walden resigned, just that it was to take an elected seat in the United States House of Representatives for a term beginning March 4.
- Kirkwood resigned to take an elected seat in the United States Senate; as lieutenant governor, Newbold succeeded him.
- All sources state Boies was sworn in on February 27, 1890, with no explanation given for the delay; it appears from primary sources that the state legislature was deadlocked, performing over one hundred votes to name the speaker, and the certification of election results was delayed,  with Larrabee remaining in office until his successor was certified.
- Represented the Republican Party.
- The election schedule changed with this term, switching to odd-numbered years and lenthening the term by nearly a year.
- Cummins resigned to take an elected seat in the United States Senate; as lieutenant governor, Garst succeeded him.
- Beardsley died in office; as lieutenant governor, Elthon succeeded him.
- Represented the Democratic Party.
- Hughes resigned to take an elected seat in the United States Senate; as lieutenant governor, Fulton succeeded him.
- Terms were lengthened from two to four years beginning with this term.
- Branstad resigned to become United States Ambassador to China; as lieutenant governor, Reynolds succeeded him.
- On May 25, 2017, Governor Reynolds appointed Adam Gregg as acting lieutenant governor but, while he has the full powers and salary of the office, he was not in the line of succession; he was elected lieutenant governor in the 2018 election and will take office January 11, 2019
- Governor Reynolds' first full term begins on January 11, 2019, and expires on January 10, 2023.
- "Constitution of the State of Iowa". Iowa General Assembly. 1857. Archived from the original on July 3, 2011. Retrieved November 8, 2014.
- "Amendments to the Constitution of Iowa". Iowa General Assembly. 1998. Retrieved November 8, 2014.
- "Constitution of the State of Iowa". Iowa General Assembly. 1846. Retrieved November 8, 2014.
- Shambaugh, Benjamin F., ed. (1903). "The Messages and Proclamations of the Governors of Iowa". The Messages and Proclamations of the Governors of Iowa. 1. Iowa City, Iowa: State Historical Society of Iowa. p. 208.
- Executive Journal of Iowa 1838–1841, Governor Robert Lucas. State Historical Society of Iowa. 1906. pp. 277–279.
- Benjamin F. Gue (1903). Iowa biography. Century History Company. p. 52.
- 1846 Const. article V, § 2.
- IA Const. art. IV, § 2
- IA Const. amendment 32.
- IA Const. art. IV, § 15
- IA Const. amendment 42.
- IA Const. art. IV, § 3.
- IA Const. amendment 41.
- IA Const. art. IV, § 17.
- 1846 Const. art V, § 18.
- "No 41st Governor for Iowa?". The Gazette (Cedar Rapids). November 5, 2010. Retrieved November 8, 2014.
- Secretary Of State, Iowa (1951). Iowa Official Register – 1951–1952. p. 97.
- Journal of the House of the General Assembly of the State of Iowa. 1890. pp. 1&ndash, 95. Retrieved September 6, 2017.