Karamürsel is a municipality and district located in the Kocaeli Province of Turkey. Situated on the south coast of the Gulf of İzmit, the district covers an area of 262 km2 and had a population of 59,676 as of 2022.
Historically known by the Greek name Praenetos before its conquest by the Ottomans, the town was renamed to commemorate Kara Mürsel. He is recognized for founding the Ottoman navy and designing distinctive galley ships known as kadırgas.