Najd

Najd is a historical region of the Arabian Peninsula that includes most of the central region of Saudi Arabia. It is roughly bounded by the Hejaz region to the west, the Nafud desert in al-Jawf to the north, ad-Dahna Desert in al-Ahsa to the east, and Rub' al-Khali to the south, although its exact boundaries cannot be determined due to varying geographical and political limits throughout history.

Administratively, Najd is divided into three main regions: the Riyadh region which features Wadi Hanifa and the Tuwaiq escarpment, which houses easterly Yamama with the Saudi capital, Riyadh since 1824, and the Sudairi region, which has its capital in Majmaah. The second region, Al-Qassim, houses the fertile oases and date palm orchards spread out in the region's highlands along Wadi Rummah in central Najd with its capital in Buraidah, the second largest Najdi city, with the region historically contested by the House of Rashid to its north and the House of Saud to its east and south. The third administrative unit is northerly Ḥa'il, which features the mountains of Jabal Shammar housing the Tayy capital of Ḥa'il.

The Najd region is where about a third of Saudi Arabia's modern population resides. It is the home of the House of Saud, from which it pursued its unification with Hejaz since the time of the Emirate of Diriyah.

The term Najd (Arabic: نجد) literally translates to "highland" in Arabic.

The Najd region is home to Al-Magar, which was an advanced prehistoric culture of the Neolithic whose center lay in modern-day southwestern Najd. Al-Magar is possibly one of the first cultures in the world where widespread agriculture and the domestication of animals occurred, particularly that of the horse, during the Neolithic period, before climate changes in the region resulted in desertification. Radiocarbon dating of several objects discovered at Al-Magar indicate an age of about 9,000 years.

In November 2017 hunting scenes showing images of what appear to be domesticated dogs resembling the Canaan dog and wearing leashes were discovered in Shuwaymis, an area about 370 km southwest of the city of Ha'il. Dated at 8,000 years before the present, these are thought of as the earliest known depictions of dogs in the world.

In the 5th century AD, the tribes of North Arabia became a major threat to the trade line between Yemen and Syria. The Ḥimyarites of Sheba decided to establish a vassal state that controlled Central and North Arabia. The Kindites, mentioned in Greek sources as the Chinedakolpitai (Greek: Χινεδακολπιται), gained strength and numbers to play that role and in AD 425 the Ḥimyarite king Ḥasan ibn 'Amr ibn Tubba’ made Ḥujr 'Akīl al-Murār ibn 'Amr the first King (Ḥujr) of Kindah. They established the Kingdom of Kinda in Najd in central Arabia unlike the organized states of Yemen; its kings exercised an influence over a number of associated tribes more by personal prestige than by coercive settled authority. Their first capital was Qaryat Dhāt Kāhil, today known as Qaryat al-Fāw.

The Ghassānids, Lakhmids and Kindites were all Kahlānī and Qaḥṭānī kingdoms which thrived in Najd. In the 5th and 6th centuries AD, the Kindites made the first real concerted effort to unite all the tribes of Central Arabia through alliances, and focused on wars with the Lakhmids. Al-Ḥārith ibn 'Amr, the most famous of their kings, finally succeeded in capturing the Lakhmid capital of al-Ḥirah in southern modern-day Iraq. Later however in about 529, al-Mundhir recaptured the city and put King Ḥārith and about fifty members of his family to death.