Istanbul is the most populous city in Turkey and the country’s economic, cultural, and historic center. It’s situated in the northwestern region of Turkey, straddling the Bosporus strait. Istanbul is among the oldest of the world’s great cities and one of the most cosmopolitan. It is renowned for influencing other cities around the world. It is famous for its astounding Byzantine and Ottoman architecture, with structures such as the Hagia Sophia, Blue Mosque, Topkapi Palace, and the Grand Bazaar.

Census in Turkey is done irregularly, with the last official census taking place in 2000. The next census is not yet scheduled. According to the data from the Turkish Statistical Institute, Istanbul had a population of 15,029,231 in 2019. Compared to other cities in Turkey, Istanbul is considered to be more diverse. With regards to religious beliefs, Istanbul is predominantly Muslim, but also hosts other religious communities including Christians and Jews. Istanbul is one of the most cosmopolitan cities in the world, housing over 15 million residents, who collectively speak numerous languages, including Turkish, English, Arabic, and Russian. The city is known for its cats, with hundreds of thousands of them roaming the streets freely. Istanbul's historic areas were added to the UNESCO World Heritage List in 1985, recognizing its rich history and vibrant culture.

The Istanbul Metropolitan Municipality (IMM) is the administrative body responsible for managing the city. The IMM is made up of the mayor and the Metropolitan Municipal Council. The mayor, who has executive powers, and the Council members are elected every five years by local residents. The IMM is responsible for strategic planning, policing, transportation, economic development, and other municipal services. On the other hand, 39 district municipalities within the city are responsible for managing local services, such as education, healthcare, and waste management.

Istanbul is Turkey's largest economic hub, contributing about 30 percent to the country's GDP. The city thrives in trade and commerce and has a vibrant culture steeped in commerce. It has one of the fastest growing metropolitan economies in the world. The Port of Istanbul, particularly the Port of Haydarpasa, handles a significant amount of cargo every year.

Istanbul's infrastructure has been a focus of significant investment, with projects such as the Yavuz Sultan Selim Bridge and the Eurasia Tunnel improving transportation in the city. The Istanbul Metropolitan Municipality has also been investing in digital infrastructure to improve the city's connectivity. Despite these efforts, the city faces challenges due to its rapid growth and the need for further improvements in transportation and utility infrastructure.