Grand Cayman, which is 22 mi (36 km) long and 8 mi (13 km) wide, is the largest of the three low-lying islands that make up this British colony. Its sister islands (Little Cayman and Cayman Brac) are almost 90 mi (149 km) north and east. The Cayman Trough between the Cayman Islands and Jamaica is the deepest part of the Caribbean.