The holiest sites in Islam are predominantly located in the Arabian Peninsula and the Levant. While the significance of most places typically varies depending on the Islamic sect, there is a consensus across all mainstream branches of the religion that affirms three cities as having the highest degree of holiness, in descending order: Mecca, Medina, and Jerusalem. Mecca's Al-Masjid al-Haram, Al-Masjid an-Nabawi in Medina and Al-Masjid al-Aqsa in Jerusalem are all revered by Muslims as sites of great importance.

Mecca is the capital of Mecca Province in the Hejaz region of western Saudi Arabia and the holiest city in Islam. It is 70 km (43 mi) inland from Jeddah on the Red Sea, in a narrow valley 277 m (909 ft) above sea level. Its last recorded population was 2,385,509 in 2022. Its metropolitan population in 2022 is 2.4 million, making it the third-most populated city in Saudi Arabia after Riyadh and Jeddah. Around 44.5% of the population are Saudi citizens and around 55.5% are foreigners from other Muslim countries. Pilgrims more than triple the population number every year during the Ḥajj pilgrimage, observed in the twelfth Hijri month of Dhūl-Ḥijjah. With over 10.8 million international visitors in 2023, Mecca was one of the 10 most visited cities in the world.