The Red Wadi (Wadi al Ahmar) lies a bit to the west of the old Roman border between Tripolitania and Cyrenaica, but if Libya splits in two it will serve quite well as the new frontier. The deadline for the fighting to resume there was March 27, but neither side is very good at organizing a battle and we will have to wait for a bit. It will probably happen in the end, though.
Libya has been a chaos of rival militias holding down local fiefdoms ever since the overthrow of Moammar Gadhafi's 42-year dictatorship in 2011, but in the past month the disintegration has accelerated. A formal division of the country into two successor states is now a real possibility, but it's unlikely to happen without some further fighting.
There has been some already. Much of the eastern half of the country, Cyrenaica, has been under the control of a coalition of tribal militias led by Ibrahim Jathran since last year. He seized control of the oil terminals on the coast through which two-thirds of Libya's oil production is exported, and set up the "Cyrenaica Political Bureau," which is acting as a proto-government in the east.