Kağıthane (Turkish pronunciation: [caɰɯtˈhaːne], in Greek was known as Glykà Nerà, Γλυκά Νερά, meaning "sweet waters"), which used to be a working class district from the sixties on, has become one of the largest regeneration and real estate development areas of the city of Istanbul, Turkey. The district is located on the European side and extends over the shores of Cendere, the stream that discharges into the Golden Horn. Cendere Valley is surrounded by Sarıyer, Eyüp, Şişli, Beşiktaş and Beyoğlu districts.
In the time of Suleiman the Magnificent Kağıthane, which was called 'Sadabad', was a large forested land and frequented by the Ottoman court for hunting, riding and all other kind of equestrian activities. In the following centuries, Sadabad became a centre of recreation with its clean waters, tulip fields, promenades and festivities. According to ancient Turkish traditions, the 6th of May was accepted as the coming of spring. On the 6th of May, during the Hıdrellez Festivals, hundreds of people from all over Istanbul would visit the Kağıthane River on boats and carts. There are a lot of engravings and paintings depicting gatherings in Sadabad, such as weddings or picnics. Later, in the 17th and 18th centuries, mansions and summer palaces were built in the area.
In the 19th and beginning of the 20th centuries, the strategically and logistically well located area was turned into a zone of industry. Kağıthane then became home to numerous factories including flour mills and the paper factories. The district was named after these paper factories and came to be called as "Kağıt hane" (paper house). Although it is known that from time to time gypsies, nomadic people, trade or hadj caravans were hosted in the region, there was no settlement therein until the late 20th century.
The settlement in Kağıthane started as illegal slums from the 1950s onwards, as the city received thousands of migrants from Anatolia, who came to work in the factories, building sites or services sector. With the passage of time, the illegal settlements were legalised and gradually replaced by residentially-zoned buildings.
Due to its central location, especially its connections with the new intra-city transport networks, and the entry into force of urban regeneration legislation, Kağıthane is transforming. To the north, the district will serve as a hub after the completion of the construction of the third airport (new airport), third bridge and three-storey under water tunnel (that will join the European side at the Hasdal junction in the district). Real estate development includes a wide range of mixed-use, shopping mall, hotel, campus, office or residential projects.
The neighbourhoods of Kağıthane include, among others, Seyrantepe, Hamidiye, Çağlayan, Merkez (centre) and Gültepe.