Iraq mainly consists of desert, but near the two major rivers (Euphrates and Tigris) are fertile alluvial plains, as the rivers carry about 60,000,000 m3 (78,477,037 cu yd) of silt annually to the delta. The north of the country is mostly composed of mountains; the highest point being at 3,611 m (11,847 ft) point, unnamed on the map opposite, but known locally as Cheekah Dar (black tent). Iraq has a small coastline measuring 58 km (36 mi) along the Persian Gulf. Close to the coast and along the Shatt al-Arab (known as arvandrūd: اروندرود among Iranians) there used to be marshlands, but many were drained in the 1990s.
The local climate is mostly desert, with mild to cool winters and dry, hot, cloudless summers. The northern mountainous regions (Kurdistan region ههرێمی کوردستان) have cold winters with occasional heavy snows, sometimes causing extensive flooding.
With its 143.1 billion barrels (2.275×1010 m3) of proved oil reserves, Iraq ranks second in the world behind Saudi Arabia in the amount of Oil reserves; yet the United States Department of Energy estimates that up to 90% of the country remains unexplored. These regions could yield an additional 100 billion barrels (1.6×1010 m3). Iraq's oil production costs are among the lowest in the world, but only about 2,000 oil wells have been drilled in Iraq, compared with about 1 million wells in Texas alone.