Worth County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 7,443. The county seat is Northwood. The county was founded in 1851 and named for Major General William Jenkins Worth (1794–1849), an officer in both the Seminole War and the Mexican–American War.

William Jenkins Worth was an American officer during the War of 1812, the Second Seminole War, and the Mexican–American War.