In regards to topographical land characteristics, geographers have categorized Arabia into three types. First is the coastal region which extends over uniformly levelled surface, and in contrast to other regions, is temperate. Second is the mountainous region with valleys, which are the heart of the country. Third is the wilderness, which due to its vast desert, is usually barren and uninhabited.
Along the western coast of Arabia, a range of mountains runs north and south, known as Jabalus-Sarāt. Some of the mountains of this range reach an altitude of 8,000, or rather 10,000 feet, but the total average altitude is quite minimal. From the centre of this range, another series of mountains, which in actuality is a combination of many smaller mountainous regions, is spread extensively to the north and south. It divides Arabia into two portions and extends towards the country’s eastern coast. This vast region, which is situated in the centre of Arabia and is significantly above sea level, is known as the Satḥ-e-Murtafa‘ Najd1. The average altitude of this region is approximately 4,000 feet. An exceedingly vast desert is situated to the north, south and somewhat to the east of the Satḥ-e-Murtafa‘ Najd. The northern desert of Arabia eventually meets the northern desert of Syria, and the southern desert, which is quite vast in area and is entirely barren land is renowned as the Ar-Rubu‘ul-Khālī. Significantly high mountain range is also located towards the south and south-east of Arabia, hence, the apex of various mountains in ‘Ummān reach an altitude of approximately 10,000 feet.
In Arabia, there are no rivers worthy of mention, however, when it rains, water level rises in river channels and ravines, which gush forth water, and at times this results in floods. However, a scarcity of water generally exists in such magnitude as one is unable to find water for hundreds of miles. Fountains are found in some places and are the source of succulence for surrounding habitation. Such fountains as have trees and gardens planted around them, surrounded by miles and miles of barren desert, are known as an oasis. In Arabia, they are considered an immense blessing. The area of Yemen is the most fertile and verdant in all of Arabia, and in contrast to other regions it possesses an abundance of ravines and springs. In the same manner, the region of Ṭā’if, which is situated at a distance of twenty miles to the south-east of Makkah, is also a pleasant and fertile region, which produces fruits of fine quality.
1 The Elevated Land of Najd (Publishers)