Istanbul has a population of 15,701,602, making it the 1st largest place we list in Turkey.
Istanbul holds 17.9% of Turkey's 87,926,082 people. Twenty years earlier the World Gazetteer recorded 9,792,428, a rise of 60%.
The 2005 figure comes from the World Gazetteer archive restored on this site. The two sources may draw the settlement's boundary differently, so treat the change as indicative rather than exact. Why figures differ.
Nearby in size
Figures are the latest available in GeoNames (CC BY 4.0), which draws on national censuses of varying dates — treat them as recent, not same-year. Country totals are UN World Population Prospects 2024 (medium variant) where the UN lists the country separately; the handful it reports under a parent state keep a GeoNames figure and are marked as such. Sources & method.