After the Wehrmacht occupied the Channel Islands on 30 June 1940, they assessed the existing defences to determine if they would be of use. The Germans found the Islands' fortifications antiquated and woefully inadequate for modern warfare.

Guernsey is the second largest island in the Channel Islands, located 27 miles (43 km) west of the Cotentin Peninsula, Normandy. It is the largest island in the Bailiwick of Guernsey, which includes five other inhabited islands and many small islets and rocks. The Bailiwick has a population of 63,950, the vast majority of whom live on Guernsey, and the island has a land area of 24 square miles (62 km2).