Istanbul city had been divided in two parts with The Bosphorous. Asian side remains on east part and extends till to Kocaeli(Izmit) border.
In Turkish, we call Anatolian side but the foreigners call Asian side usually.
The north of Asian side looks to Black Sea, then it is seperated from Europeside with Bosphorous and continues true to Marmara Sea in south. The Princess Islands in Marmara Sea also includes to Asian side.
Istanbul is the only one city which is made connecting two seas to each other and the sea is passing from inside of the single city.
