Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in West Asia that occupies the bulk of the Arabian Peninsula. Covering a land area of approximately 2,149,690 km2 (830,000 sq mi), it is the fifth-largest country in Asia and the twelfth-largest in the world. It is bordered by the Red Sea to the west, Jordan, Iraq, and Kuwait to the north, the Arabian Gulf, Bahrain, Qatar, and the United Arab Emirates to the east, Oman to the southeast, and Yemen to the south. The Gulf of Aqaba in the northwest separates it from Egypt and Israel. Riyadh is the capital and largest city, while other major centers include Jeddah and the two holiest cities in Islam, Mecca and Medina.
Pre-Islamic Arabia, the territory that constitutes Saudi Arabia, was the site of several ancient cultures and civilizations; the archaeological study of the prehistory of Saudi Arabia has identified some of the earliest traces of human activity outside Africa. Islam emerged in what is now Saudi Arabia in the early seventh century. Islamic prophet Muhammad united the population of the Arabian Peninsula and created a single Islamic religious polity. Following his death in 632, his followers expanded Muslim rule beyond Arabia, conquering territories in North Africa, Central, South Asia and Iberia within decades. Arab dynasties originating from modern-day Saudi Arabia founded the Rashidun (632–661), Umayyad (661–750), Abbasid (750–1517), and Fatimid (909–1171) caliphates, as well as numerous other Muslim states in Asia, Africa, and Europe.
Saudi Arabia was founded in 1932 by King Abdulaziz, who united Hejaz, Najd, parts of Eastern Arabia and South Arabia into a single state through a series of military and political campaigns beginning in 1902. The Kingdom is the Third Saudi State and the successor to the First Saudi State (1727–1818) and the Second Saudi State (1824–1891). The country has since been governed as an absolute monarchy under the House of Saud. In its Basic Law, Saudi Arabia defines itself as a sovereign Arab Islamic state with Islam as its official religion and Arabic as its official language. The ultraconservative Wahhabi religious movement within Sunni Islam was the prevailing political and cultural force until the 2000s. The Saudi government has attracted criticism for various policies such as its intervention in the Yemeni Civil War, restrictions on political and civil liberties, and poor human rights record. Since the mid-2010s, Saudi Arabia has instituted limited and gradual reforms to liberalize social, cultural, and religious life.
Saudi Arabia is considered both a regional and middle power, in addition to being a major non-NATO ally of the United States. Since petroleum was discovered in the country in 1938, the kingdom has become the world's second-largest oil producer and leading oil exporter, controlling the world's second-largest oil reserves and sixth-largest gas reserves. Saudi Arabia is categorized as a World Bank high-income economy and is the only Arab country among the G20 major economies. The Saudi economy is the largest in the Middle East and the world's nineteenth-largest by nominal GDP and seventeenth-largest by PPP. Ranking very high in the Human Development Index, Saudi Arabia offers free university tuition, no personal income tax, and free universal health care. With its dependence on foreign labour, Saudi Arabia has the world's third-largest immigrant population, with foreign-born residents comprising roughly 40% of the population. Saudi Arabians are among the world's youngest people, with approximately half being under 25 years old. Saudi Arabia is a member of the Gulf Cooperation Council, United Nations, Organisation of Islamic Cooperation, Arab League, and OPEC, as well as a dialogue partner of the Shanghai Cooperation Organisation.
Following the amalgamation of the Kingdom of Hejaz and Nejd, Abdulaziz issued a royal decree on 23 September 1932 naming the new state al-Mamlaka al-ʿArabiyya as-Suʿūdiyya (Arabic المملكة العربية السعودية), which is normally translated as "the Kingdom of Saudi Arabia" in English, but literally means "the Saudi Arab Kingdom", or "the Saudi Kingdom of Arabia" (compare the Hashemite Kingdom of Jordan).
The word "Saudi" is derived from the element as-Suʿūdīyya in the Arabic name of the country, which is a type of adjective known as a nisba, formed from the dynastic name of the Saudi royal family, the Al Saud (Arabic: آل سعود). Its inclusion expresses the view that the country is the personal possession of the royal family. Al Saud is an Arabic name formed by adding the word Al, meaning "family of" or "House of", to the personal name of an ancestor. In the case of Al Saud, this is Saud ibn Muhammad ibn Muqrin, the father of the dynasty's 18th-century founder, Muhammad bin Saud.
There is evidence that human habitation in the Arabian Peninsula dates back to about 125,000 years ago. A 2011 study found that the first modern humans to spread east across Asia left Africa about 75,000 years ago across the Bab-el-Mandeb connecting the Horn of Africa and Arabia. The Arabian Peninsula is regarded as central to the understanding of evolution and dispersals of humanity. Arabia underwent an extreme environmental fluctuation in the Quaternary that led to profound evolutionary and demographic changes. Arabia's rich Lower Paleolithic record, marked by numerous Oldowan-like sites, indicates a significant role in the early hominin colonization of Eurasia.
In the Neolithic period, prominent cultures such as Al-Magar, whose centre lay in modern-day southwestern Najd, flourished. Al-Magar could be considered a "Neolithic Revolution" in human knowledge and handicraft skills. The culture is characterized as being one of the world's first to involve the widespread domestication of animals, particularly the horse. Al-Magar statues were made from local stone, and it seems that the statues were fixed in a central building that might have had a significant role in the social and religious life of the inhabitants.
In 2017, hunting scenes showing images of most likely domesticated dogs (resembling the Canaan Dog) were discovered in northwestern Saudi Arabia. These rock engravings date back more than 8,000 years, making them the earliest depictions of dogs in the world.
At the end of the 4th millennium BCE, Arabia entered the Bronze Age; metals were widely used, and the period was characterized by its 2 m high burials which were simultaneously followed by the existence of numerous temples that included many free-standing sculptures originally painted with red colours.
In May 2021, archaeologists announced that a 350,000-year-old Acheulean site named An Nasim in the Hail region could be the oldest human habitation site in northern Saudi Arabia. Paleolithic artefacts are similar to material remains uncovered at the Acheulean sites in the Nefud Desert.
The earliest sedentary culture in Saudi Arabia dates to the Ubaid period at Dosariyah. Climatic change and the onset of aridity may have brought about the end of this phase of settlement, as little archaeological evidence exists from the succeeding millennium. The settlement of the region picks up again in the period of Dilmun in the early 3rd millennium. Known records from Uruk refer to a place called Dilmun, associated on several occasions with copper, and in later periods it was a source of imported woods in southern Mesopotamia. Scholars have suggested that Dilmun originally designated the Eastern Province, notably linked with the major Dilmunite settlements of Umm an-Nussi and Umm ar-Ramadh in the interior and Tarout on the coast. It is likely that Tarout Island was the main port and the capital of Dilmun. Mesopotamian inscribed clay tablets suggest that, in the early period of Dilmun, a hierarchical organized political structure existed. In 1966, an earthwork in Tarout exposed an ancient burial field that yielded a large statue dating to the Dilmunite period (mid 3rd millennium BCE). The statue was locally made under the strong Mesopotamian influence on the artistic principle of Dilmun.