Algiers is the capital city of Algeria as well as the capital of the Algiers Province; it extends over many communes without having its own separate governing body. With 2,988,145 residents in 2008 and an estimated 3,004,130 residents in 2025 in an area of 1,190 square kilometres (460 sq mi), Algiers is the largest city in Algeria, the third largest city on the Mediterranean, sixth in the Arab World, and 29th in Africa. Located in the north-central portion of the country, it extends along the Bay of Algiers surrounded by the Mitidja Plain and major mountain ranges. Its favorable location made it the center of Ottoman and French cultural, political, and architectural influences for the region, shaping it to be the diverse metropolis it is today.

Algiers was formally founded in 972 AD by Buluggin ibn Ziri, though its history goes back to around 1200-250 BC when it was a small settlement of Phoenicians that practiced trade. It was caught under control of many nations and empires such as Numidia, the Roman Empire and the Islamic caliphates, as it went on to become the capital of the Regency of Algiers from 1516 to 1830 AD, then under the control of France due to an invasion that ranked Algiers as capital of French Algeria from 1830 to 1942 AD which temporarily merged with Free France from 1942 to 1944 AD, then back again to French Algeria from 1944 to 1962 AD, and finally capital of Algeria from 1962 to present day after the Algerian Revolution.

Algiers is the main tourist destination in Algeria due to its many museums, art galleries and cultural centers, but most notably the historic center that is classified as a UNESCO World Heritage Site, the Casbah which houses many traditional Algerian and Ottoman/Andalusian style buildings, while the French side of the city is bigger and has many distinct architectural styles that showcase trends over the decades whether they were local or international; Al bidha meaning « the white » is what the city's called because of its white washed buildings whether they originated from colonial powers or local populations. The Host city of the 1975 Mediterranean Games and other major African and international sports events, Algiers is also the seat of the Consultative Council of the Arab Maghreb Union. Numerous Algerian multinational companies are based in the city, such as Sonatrach Petroleum Corporation and Air Algérie.