Çatalca is a municipality and district located in the Istanbul Province of Turkey. Situated in East Thrace, it lies on the ridge between the Marmara Sea and the Black Sea.
The district covers an area of 1,142 km², making it the largest district in Istanbul Province by size. As of 2022, its population was recorded at 77,468 residents.
The local economy and demographics are characterized primarily by farming and the ownership of vacation homes. The area is a frequent destination for families from Istanbul who visit for weekend activities such as hiking and picnics.