Squares, which are one of the architectural features of cities, have an important place in the field of history of architecture. In the literature, starting from the first ages especially, the notion of square is reached through architectural factors like agora, forum, piazza and etc. and regional and periodic typologies were tried to be produced. However, these studies are limited to general studies, such as Ancient Greek squares, Ancient Roman squares, Medieval squares, Renaissance squares, etc. and the large urban squares known around the world. Neighbourhood squares have been ignored. In addition, because the concept of the square in the Ottoman period was tried to be evaluated through the concept of the square in European countries in the sources, the Ottoman's unique understanding of the square have been overlooked. In this study, Kadirga Square, located in the historical peninsula of Istanbul, has been chosen among the Ottoman squares. Kadirga Square, its functions and its historical process have been examined by taking the notion of square into the centre. The function and effect of Kadirga Harbour, the formation process of Kadirga Square, the elements forming the square and its intended uses, the transformation process into a park and the process of the disappearance of the square's functions have been evaluated in terms of the history of architecture. Through Kadirga Square in the Ottoman period, it was aimed to contribute to the field of history of architecture by making an evaluation of a neighbourhood square that was not designed.