Peninsula, << puh NIHN suh luh, >> is an area of land that is nearly surrounded by water. Peninsulas are usually long, narrow strips, but they also may span vast areas. Some peninsulas are joined to the mainland by a broad base. Others are connected by a narrow strip of land, called an isthmus (see Isthmus ). Arabia, the largest peninsula, covers about 1,000,000 square miles (2,600,000 square kilometers).