Baku is the capital and largest city of Azerbaijan, as well as the largest city on the Caspian Sea and of the Caucasus region.^[9] Baku is located 28 metres (92 ft) below sea level, which makes it the lowest lying national capital in the world and also the largest city in the world located below sea level. Baku lies on the southern shore of the Absheron Peninsula, alongside the Bay of Baku. Baku's urban population was estimated at two million people as of 2009. Baku is the primate city of Azerbaijan - it is the sole metropolis in the country, and about 25% of all inhabitants of the country live in Baku's metropolitan area.
Baku is divided into twelve administrative raions and 48 townships. Among these are the townships on the islands of the Baku Archipelago, and the town of Oil Rocks built on stilts in the Caspian Sea, 60 kilometres (37 miles) away from Baku. The Inner City of Baku, along with the Shirvanshah's Palace and Maiden Tower, were inscribed as a UNESCO World Heritage Site in 2000.
The city is the scientific, cultural, and industrial centre of Azerbaijan. Many sizeable Azerbaijani institutions have their headquarters there. In recent years, Baku has become an important venue for international events. It hosted the 57th Eurovision Song Contest in 2012, the 2015 European Games, 4th Islamic Solidarity Games, the European Grand Prix in 2016, the Azerbaijan Grand Prix since 2017, hosted the final of the 2018–19 UEFA Europa League, and was one of the host cities for UEFA Euro 2020. The Baku International Sea Trade Port is capable of handling two million tonnes of general and dry bulk cargoes per year.
The city is renowned for its harsh winds, which is reflected in its nickname, the "City of Winds".

Ganja is Azerbaijan's third largest city, with a population of around 335,600. The city has been a historic and cultural center throughout most of its existence. It was the capital of the Ganja Khanate until 1804;
after Qajar Iran ceded it to the Russian Empire following the Treaty of Gulistan in 1813, it became part of the administrative divisions of the Georgia Governorate, Georgia-Imeretia Governorate, Tiflis Governorate, and Elizavetpol Governorate. Following the dissolution of the Russian Empire and the Transcaucasian Democratic Federative Republic, it became a part of the Azerbaijan Democratic Republic, followed by Azerbaijan SSR, and, since 1991, the Republic of Azerbaijan.

Sumgait is a city in Azerbaijan, located near the Caspian Sea, on the Absheron Peninsula, about 31 kilometres (19 miles) away from the capital Baku. The city has a population of around 345,300, making it the second largest city in Azerbaijan after Baku.
The city has a territory of 83 square kilometres (32 sq mi). It was founded as a suburb of Baku in 1944 and received city status on November 22, 1949, growing into a major industrial center during the Soviet period. The municipality of Sumgait also includes the settlements of Jorat and Haji Zeynalabdin. It is home to Sumqayit State University.

Mingachevir is the fourth-largest city in Azerbaijan with a population of about 106,000. It's often called the "city of lights" because of its hydroelectric power station on the Kur River, which divides the city down the middle.
The current city was founded in 1948, partly by German prisoners of war captured during World War II. Mingechevir is also home to Mingachevir Polytechnic Institute. The city forms an administrative division of Azerbaijan. The district is located 323 km from Baku and 17 km from the Baku-Tbilisi railway. Geographically, the region is located in the center of the republic on both sides of the Kura River.

Xırdalan (Khyrdalan) is a city, municipality and the capital of the Absheron District of Azerbaijan. It has a population of 95,200. Khyrdalan is home of country's biggest brewery Baltika Baku, previously known as Khyrdalan . A monument to Egyptian president Hosni Mubarak was erected in 2007 in the city. Similarly, a statue of Heydar Aliyev was erected in Cairo in 2008. In the wake of the 2011 Egyptian protests, the Azerbaijani opposition, led by the Musavat Party, demanded the demolition of the statue, calling it a "worship of idols". On 8 June 2011, the statue was taken down following Mubarak's resignation.
On 29 November 2006, the settlement gained city status after its approval by the National Assembly of Azerbaijan.