Oldwick is an unincorporated community and census-designated place (CDP) located within Tewksbury Township in Hunterdon County, in the U.S. state of New Jersey. The area is served as United States Postal Service ZIP Code 08858. As of the 2000 United States census, the population for ZIP Code Tabulation Area 08858 was 177. The 2010 census data indicate a population of 144, comprising 68 housing units.

Henry Melchior Muhlenberg, was a German-born Lutheran clergyman and missionary. Born in Einbeck, Muhlenberg immigrated to the Province of Pennsylvania in response to demands from Lutherans for missionary work in the colony. Muhlenberg was integral to the founding of the first Lutheran church body or denomination in North America, and is considered the patriarch of the Lutheran Church in the United States.