Same-same for South Africa:
During the first Metis rebellion, the British had to get permission from the USA to send their troops through Minnesota to get to Manitoba. The Canadian route from lake Superior was barely traversable by canoe. By the second (and last) rebellion, the troops and to disembark at the end of the CPR rail line, north of Lake Superior, and march 60 miles along the shore on the ice to get to the other part where the rail was build eastward from the west. Then they took the train west to take on the Metis. When they were done, they were able to take the finished rail all the way back to eastern Canada.
That’s what a geographical impediment does.
The Egyptians had travelled south from the Red Sea - Hapshetsut’s temple commemorates the voyages of her reign (about 1460BC), with reliefs that show the locals of the Land of Punt. (Presumably showing they made it as far as the fourth down?) The carvings show obviously southerly African people and scenes, and they brought back assorted spices. This has variously been suggested to be Somalia or even as far south as Tanzania with its spices.
There’s evidence of East Coast trade that linked Zanzibar or further south with Mesopotamia as far back as the 3rd millennium BCE.