Fred C. Koch (1900–1967) was an American chemical engineer and entrepreneur who developed innovative oil refining processes and founded businesses that evolved into Koch Industries, which later became the largest privately held corporation in the United States.

David H. Koch (1940–2019) was an American businessman, philanthropist, and executive vice president of Koch Industries. A co-owner of the company, he became widely known for major charitable donations supporting medical research, education, and cultural institutions.

Charles G. Koch (born 1935) is an American businessman and chairman of Koch Industries. Under his leadership, the company grew into the world’s largest privately held corporation, expanding from oil refining into diverse global industrial operations.

Herman Knickerbocker (1779–1855) was a New York lawyer, Federalist politician, and U.S. congressman who represented the Albany region from 1809 to 1811. A descendant of early Dutch settlers, he later managed the Knickerbocker family estate.

Peter Kiewit (1900–1979) was an American construction executive who transformed his family’s Omaha contracting firm into the global Kiewit Corporation. Under his leadership, the company built major infrastructure projects and became one of North America’s largest construction firms.

Jim Kaat (born 1938) is a Dutch American former Major League Baseball pitcher and broadcaster. Over a 25-year career he won 16 Gold Glove Awards and later became an Emmy-winning baseball analyst for NBC, ESPN, and the Yankees Network.

Willem Kieft (c.1597–1647) served as Director of New Netherland from 1638 to 1647. His authoritarian leadership and conflicts with settlers and Native Americans sparked Kieft’s War, leading to his recall by Dutch authorities.

Meindert De Jong (1906–1991) was a Dutch-born American author of children’s books who won the Newbery Medal for The Wheel on the School and the Hans Christian Andersen Medal for his lasting contributions to children’s literature.

John Jay (1745–1829) was a Founding Father, diplomat, jurist, and statesman who served as president of the Continental Congress, first Chief Justice of the United States, and governor of New York, shaping the early republic.

Famke Janssen (born 1965) is a Dutch actress and former fashion model who gained international fame as a Bond villain in GoldenEye and as Jean Grey in the X-Men film series. She has also directed films.

Henry “Hank” Jansen (d. 2002) was a transportation entrepreneur who founded Lynden Transport and pioneered commercial trucking between the Pacific Northwest and Alaska after construction of the Alaska Highway, building Lynden into a major logistics company.

Guy Vander Jagt (1931–2007) was a Michigan Republican who served 26 years in the U.S. House of Representatives. A Hope College graduate, he later helped establish Dutch American Heritage Day and was honored by the Netherlands.