Short answers, pulled from the story.
Hajiganj Fort rose soon after Subahdar Islam Khan established the Mughal capital at Dhaka. The exact date of construction remains uncertain but it predates other examples such as Sonakanda Fort and Idrakpur Fort.
The historical name of the fort and its surrounding area was Khizirpur. This site stands today at Hajiganj locality of Narayanganj, Bangladesh on the western bank of Shitalakshya River.
Evidence points to the site being primarily occupied only during the rainy season when river currents shifted. Occupants likely relied on tents for shelter because there are no stone foundations or permanent housing within the interior.
The fort's sole gateway is positioned exclusively on the river-facing side to control all incoming traffic from the Shitalakshya River. A pentagonal gateway sits within a rectangular structure that frames its unique shape with engraved rectangular arches on both sides.
This structure served a singular purpose: to prevent Magh and Portuguese raids on the growing city of Dhaka. It formed part of a unified defense system alongside Sonakanda Fort and Idrakpur Fort to counter pirate activity anticipated heavily during wet months.