Denison Island is an Antarctic island lying 0.5 kilometres (0.25 nmi) west of Beall Island in the Windmill Islands. It was first mapped from air photos taken by USN Operation Highjump and Operation Windmill in 1947 and 1948. It was named by the US-ACAN for Dean R. Denison, auroral scientist and member of the Wilkes Station party of 1958.