It is an Anatolian headland pointing north to Gulf of İzmit which is a part of Marmara Sea.
The strategic importance of the headland was noticed by the Roman Emperor Constantine I who founded the town of Helenopolis.
Hersek headland is also known as the place where the Ottoman Empire (then only a principality) proclaimed independence.
On 27 July 1302, Ottoman armies defeated Byzantine armies which tried to relieve the city of Nicea (modern İznik) from Ottoman siege in the battle of Koyunhisar.
The İzmit Bay Bridge is under construction between Hersek headland and Dilovası on the opposite side of the gulf.