Kogin Birim yana daya daga cikin manyan kogunan Kogin Pra a Ghana kuma mafi muhimmancin yankin da ake samar da lu'u-lu'u, yana ratsa mafi yawan fadin yankin Gabas. Kogin yana hawa a gabashin Dutsen Atewa, yana gudana arewa ta tsakanin ratar tsakanin wannan zangon da yankin Kwahu Plateau, sa'annan yayi tafiya kusan kudu maso yamma har sai ya haɗu da Pra. Ya ba da sunansa ga dutsen Birimian, wanda ke samar da mafi yawan zinare a yankin. Ghana ce ta biyu mafi girma a duniya wajen samar da gwal a Afirka. Kogin Birim yana cikin yankin Garkuwan Manya na yankin Afirka ta Yamma, wanda wasu kyawawan duwatsun Birimian na farkon Proterozoic suka mamaye shi. Wadannan duwatsun sun bayyana sun samo asali ne daga tsakiyar tsaunukan tsaunuka, wanda ya samar da wani kwari wanda ya yi karo da shi kuma ya hau kan garkuwar Man garken Craton na Afirka ta Yamma kuma an matse shi don samar da jerin ninki gaba daya da ke tafiya a arewa maso gabas. Duwatsun Birimiyan sun hada da tsarin Akwatian, wanda aka sanyawa sunan garin Akwatia a cikin kwarin Birim, wanda ya samar da sama da carat 100,000,000 (Kilogiram 20,000) na lu'ulu'u.