Gerald Joseph Theunissen, or Jerry Theunissen (born August 19, 1933), is the vice president of Jeff Davis Bank in Jennings, Louisiana, USA, and served as a member of the Louisiana House of Representatives from District 37 (1992–1996) and as the state senator from District 25 (1996–2008). He was term-limited in 2007 from seeking a fourth term in the upper chamber of the legislature.
Theunissen was elected twice to the House in 1991 and 1995 and in his first state Senate race in 1996 as a Democrat. He later switched to Republican affiliation and is listed in the official records as a member of the GOP in the 2000–2004 legislative session. He was also succeeded by a Republican, Dan Morrish.
Theunissen graduated in 1951 from Jennings High School in Jennings, the seat of Jefferson Parish. He attended the University of Louisiana at Lafayette, then the University of Southwestern Louisiana, but he received his bachelor's degree from the University of Nebraska at Omaha. He is a retired lieutenant colonel from the United States Air Force, in which he served from 1953 to 1974. He has been active in Jennings civic and community affairs, including membership on the Louisiana Advisory Commission on Pesticides from 1985 to 1991. In 1985, the Jennings Rotary International gave him its "Outstanding Community Service Award". He has served on the Jennings Industrial Development Board and as state director of the National Agricultural Aviation Association, the interest group of crop dusters. He is also a past president of the Greater Jennings Chamber of Commerce. Theunissen, who is Roman Catholic, is wed to the former Patricia Reaud (born ca. 1929).
Theunissen is a small town that has the only wine estate, the Theunissen Wine Farm, in the Free State province of South Africa. It was founded by Boer War Commandant Helgaardt Theunissen. Theunissen has a small community (mostly farmers and miners) which supports the local businesses.
The founding of Theunissen and its history goes hand in hand with the development of the railway system in the Orange Free State (OFS). When gold was discovered in the Witwatersrand, railways to the new gold fields were a necessity. During this period there were no railways in the OFS and the Transvaal. The nearest railway lines were Kimberley and Pietermaritzburg. Connecting to the coastal ports from the Witwatersrand was vital. A race started from the Natal and Cape coastal ports to connect with the gold fields. In 1887 the Cape government received a concession from the OFS government to build a railway line through the OFS. This railway line was completed in sections which were opened on the following dates:
Theunissen is a Dutch patronymic surname meaning "son of Theunis", a nickname for Anthonius. People with this surname include: