Oranje fort is the first heritage fort from the Dutch, which was established on May 26, 1607 by Cornelis Matclief de Jonge and being named Fort Orange by Francois Witlentt in 1609 during the reign of Sultan Mudafar. Fort Orange was originally derived from traces of an old fort that built by the Portuguese and inhabited by Malays and being named as Fort Malay. This fort is now becomes the historical sights in the city of Ternate were less well maintained and has not been managed well by the government. Today, the fort was used as a dormitory for Police and the Army, and it located strategicaly in the center of Ternate city, precisely in Gamalama village.

Inside the Fort Oranje there was Dutch governor mansion, and today becomes an Office of Culture and Tourism of Ternate; there is also elevated wells, wells with a height of 5 meters above sea level.
This fort is in the shape of trapezoid-shaped and stands on an area of 12,680 mē and it has 4 pieces bastion at each corner. The height of the wall at this fort is about 5 meters with a slope of 4 degrees. The thickness of the outer wall of the castle building is about 1 meter. Meanwhile, the wall inside the castle has a thickness of 0.75 meters.

On top of this castle, there is a rampart castle wall or bypass that connects the four bastions at each corner. Rampart is located at a height of about 3.5 meters from the ground and it has a distance for about 1.1 meters of altitude wall.
On both the inside corner of the bastion, which is located in the Northwest and Northeast, there is a ramp measuring 15 x 3 meters to get to the top of the bastion. In addition, there are also two pieces of ladder-shaped semi-circle on the inside of the main gate and the bastion in the Southwest. Meanwhile, above the main gate there is a large bell which is supported by two large wooden beams. Originally, the artificial bell made by Perio Diaz Bocarro in 1603 was imported directly from Portugal, and was placed in the castle Gamlamo. However, when the Portuguese left Ternate, the bell was moved by VOC and hung at the entrance of the fort Oranje. Until 1950 this bell was attached there, and since 1951 was removed and stored at the Catholic Church (Batu Church) in Ternate.