Looking at any generic map of the Roman Empire, it seems like for Roman control of North Africa everyone just drew a line mirroring the coastline a few miles inward for the most part. How deep into the Sahara did Roman control go at its peak? Were the tribes of the Sahara outside of Roman reach a constant threat or a friendly neighbour?
Not to discourage any further answers but you'll probably like this older post:
To what extent were the Romans in contact with native African tribes? How deeply did Rome explore, but not necessarily conquer or colonize, the African continent? by /u/cleopatra_philopater