Ironbottom Sound
In early July, a U.S. reconnaissance flight observed that the Japanese were building an airfield on Guadalcanal, across Ironbottom Sound from Tulagi. Thus, on July 10, Admiral Nimitz ordered the undertaking of Operation Watchtower, to immediately attack, seize, and hold the Solomon Islands of Guadalcanal and Tulagi. As COMSOPAC, Ghormley would command the operation, with the landing on Guadalcanal to take place on August 7.