Karasu is a district and town located in the Sakarya Province of northern Turkey. It serves as a regional center situated within the Marmara region, positioned along key transportation routes connecting various parts of the country.
The area is characterized by its proximity to the Black Sea coast and its role as a hub for local commerce and agriculture. While it functions as an urban center for the surrounding district, it maintains the cultural and geographical characteristics typical of the Sakarya region.