Sanaa is located on a plain of the same name, the '''Haql Sanaa''', which is over 2,200m above sea level. The plain is roughly 50–60 km long north-south and about 25 km wide, east-west, in the area north of Sanaa, and somewhat narrower further south. To the east and west, the Sanaa plain is bordered by cliffs and mountains, with wadis coming down from them. The northern part of the area slopes gently upward toward the district of Arhab, which was historically known as ''al-Khashab''. Much of the Sanaa plain is drained by the Wadi al-Kharid, which flows northward, through the northeastern corner of the plain, towards al-Jawf, which is a broad wadi that drains the eastern part of the Yemeni highlands. The southern part of the plain straddles the watershed between the al-Kharid and the Wadi Siham, which flows southwest towards the Yemeni Tihama.