Macin Port lay on the banks of the Barito River, around twenty kilometers from its mouth. In this, it somewhat resembled Pontianak, the capital of Lanfang Overseas Province. Both stood near river mouths, yet were in fact river port cities. However, their proximity to the sea meant ocean-going vessels could still enter without difficulty.
The Barito River was one of Borneo's major rivers, stretching over eight hundred kilometers and boasting a drainage basin of as much as one hundred thousand square kilometers. The entire island of Borneo was only a little over seven hundred thousand square kilometers, meaning the Barito River basin alone accounted for one-seventh of the whole island.
Moreover, two-thirds of the Barito River was navigable, further strengthening the status of Banjarmasin city near its mouth.
This was also the principal reason East Africa had chosen to develop this city. By controlling Banjarmasin, it could use it as a foothold and effectively control nearly one hundred thousand square kilometers of land in southern Borneo.
The operation by Lin Yaozu's unit to clear out the natives had in fact proceeded upstream along the Barito River, deep into the heart of the rainforest.
The Barito River played an even more prominent role in the local economy. East Africans obtained timber, pepper, rice, rubber, and other agricultural products along its banks, as well as abundant mineral resources such as coal and iron ore. With the Barito River's developed shipping routes, all of these could be gathered in Banjarmasin city, simply processed and sorted, then transported to East Africa or exported directly to regions such as Europe and Asia.
As a colony, East Kalimantan's economy and industry naturally existed in dependence on East Africa. Although East Kalimantan's market did not currently provide much of a boost to East Africa, it had become