The Ramlat al-Sab'atayn (Arabic: رملة السبعتين, lit. 'Sand of the Two Sevens') is a desert region that corresponds with the northern deserts of modern Yemen (Al-Jawf, Marib, Shabwah governorates) and southwestern Saudi Arabia (Najran province).
It comprises mainly transverse and seif dunes and covers an area of about 100 by 240 kilometres (60 by 150 mi), roughly 26,000 square kilometres (10,000 sq mi).
Ḥaḍramawt (Hadrami: 𐩢𐩳𐩧𐩣𐩩, romanized: ḤḌRMT; Sabaic, Minaic, Qatabānic: 𐩢𐩳𐩧𐩣𐩥𐩩, romanized: ḤḌRMWT) was an ancient South Semitic-speaking kingdom of South Arabia (ancient Yemen) which existed from the early 1st millennium BCE till the late 3rd century CE in the area currently named after it in the region of the Ṣayhad desert.
The kingdom of Ḥaḍramawt was one of the six ancient South Arabian kingdoms of ancient Yemen, along with Sabaʾ, Maʿīn, Qatabān, Ḥimyar, and Awsān. Little is known about Ḥaḍramawt compared to the other early South Arabian states.