The Sultanate of Oman is the second-largest country after Sa'udi Arabia on the Arabian Peninsula, with an area officially estimated at 212,460 sq km (82,031 sq mi). Comparatively, the area occupied by Oman is slightly smaller than the state of Kansas. Oman's territory includes the tip of the strategically important Ra's Musandam, which juts into the Strait of Hormuz. Oman's part of the peninsula is separated from the rest of the country by the territory of the United Arab Emirates (UAE). Oman proper extends 972 km (604 mi) NE – SW and 513 km (319 mi) SE – NW . It is bordered on the N by the Strait of Hormuz, on the NE by the Gulf of Oman, on the E and S by the Arabian Sea, on the SW by the People's Democratic Republic of Yemen (PDRY), on the W by the Ar-Rub' al-Khali (Empty Quarter) and Sa'udi Arabia, and on the NW by the United Arab Emirates. The total estimated boundary length is 3,466 km (2,154 mi), of which 2,092 km (1,300 mi) is coastline.