Joseph Hubert Diss Debar (March 6, 1820 - January 13, 1905) was the designer of the Great Seal of West Virginia and the state's first commissioner of immigration. Born near Strasbourg, France, Diss Debar was educated in the classics and the sciences. He was fluent in several languages and a talented artist. Diss Debar came to the United States in 1842 and moved to Parkersburg in 1846 as a land agent for John Dumas, who represented the claims of French veterans of the American Revolution in regard to land bonuses. Diss Debar resided in present West Virginia for the next 29 years, during which time he created numerous sketches of people and places of the era. He lived in Parkersburg and at St. Clara, a Doddridge County German-Swiss immigrant colony which he founded and named for his first wife, Clara Levassor, who had died in childbirth.

A supporter of the movement to create West Virginia, Diss Debar was commissioned in 1863 to design the Great Seal. Seeing the assignment in part as an opportunity to promote the new state's natural resources and economic potential, he created a two-sided medallion whose front depicts a farmer, a miner, the state motto, and other symbols. In 1864, he was appointed commissioner of immigration and worked in this capacity to recruit labor and landowners from abroad until 1871. Diss Debar involved the state in the 1867 Paris Exposition, winning a prize for the petroleum exhibit from the West Virginia oil fields. As immigration commissioner he produced The West Virginia Hand-Book and Immigrant's Guide in 1870. The Swiss colony at Helvetia was founded during his tenure, though it is uncertain whether he had any role in the project.

Diss Debar served in the legislature from Doddridge County in 1864, and in 1872 he supported the Liberal Republicans in their bid to come to terms with ex-Confederates in ending Radical Reconstruction in West Virginia. He died in Philadelphia.