Ambergris Cay is an island within the Turks and Caicos Islands. It was named for valuable deposits of ambergris, a waxy substance that migrating humpback whales secrete, found on the 8 miles (13 km) of shoreline. The island is approximately four miles long, one mile (1.6 km) wide, and 1,100 acres (4.5 km²) in total.