Cowpox children. In 1796, British medical practitioner Edward Jenner tested the theory that cowpox could protect someone from being infected by smallpox. Although cowpox originates on the udder of cows, Jenner took his sample from a milkmaid, Sarah Nelmes. Jenner extracted the pus of one of the lesions formed by cowpox on Nelmes to another individual who never had smallpox, James Phipps. He eventually developed a scab and fever that was manageable. Approximately six weeks later, Jenner then introduced an active sample of the smallpox virus into Phipps to test the theory. After being observed for an extended amount of time,
Jenner, California build a house in what became known as Jenner Gulch, the site of the town. Stillwater Cove Regional Park, located north of Jenner, features picnic facilities, beach access, and a historic one-room schoolhouse. Jenner received media attention in 2004 after the bodies of Lindsay Cutshall and Jason S. Allen were discovered on Fish Head Beach just north of town. The incident became known as the Jenner, California double-murder of 2004. According to the United States Census Bureau, the CDP covers an area of 2.4 square miles (6.2 km²), 2.1 square miles (5.5 km²) of it land, and 0.3 square miles