Koja is a subdistrict of North Jakarta, Jakarta, Indonesia. It is known as the location of Kampung Tugu, a historic Portuguese-influenced neighborhood in North Jakarta.
Koja contains the eastern section of Tanjung Priok Port (which contains the Container Terminal 1, Container Terminal 3, and Koja Container Terminal), Jakarta's main port. The Sunter Canal flows to the sea via Koja, its outlet lies on the boundary between Koja Subdistrict and Cilincing Subdistrict.
The boundaries of Koja is Jakarta Bay to the north, Laksamana Yos Sudarso Tollway to the west, Pelabuhan Minyak - Kali Baru - Kramat Jaya Road - Kali Cakung to the east, and Kali Batik to the south.
The descendants are Portuguese speaking people who had become the slaves of the Dutch when they took over Malacca in 1641. Their Dutch masters set them free in 1661, only after they disowned their Portuguese traits, including by converting to Protestantism from Catholicism, and changing their names to Dutch-sounding ones.
They are given a scrap of land, 10 kilometers east of old Batavia in what is now Tugu Administrative Village in Koja Subdistrict, one of them was Melchior Leydekker (not a slave). Melchior Leydekker is a Dutch doctor of medicine and theology who was placed in Batavia (1675) as he was at that time the son-in-law of the Governor General Abraham van Riebeeck. This new area, called Tugu, was developed as a neighborhood for the slave-released Mardijker people (free men). This area, now called Kampung Tugu, is the oldest Christian neighborhood in the west of Indonesia. Several buildings in this neighborhood dates back to the 17th century, such as the Tugu Church, thought to be built between 1676-1678.
The neighborhood still exists today, and retains its own distinct culture characteristic of Jakarta, such as the Portuguese-influenced musical style Kroncong Tugu spoken in the extinct Papia Tugu language.