WCW was essentially composed of:
1) NWA: Mid-Atlantic (JCP), Central States, St. Louis, Championship Wrestling from Georgia (Ole Anderson group's shares of GCW), Championship Wrestling from Florida. All merged into "NWA World Championship Wrestling".
2) UWF: Bill Watts - (apparently not the tape library though). Merged with NWA WCW though UWF was independent and not a member of NWA.
3) The name "World Championship Wrestling" and the Turner Broadcasting (TBS) Time slot which were purchased from Vince McMahon who had purchased them from Jack & Jerry Briscoe's shares of Georgia Championship Wrestling.
Ted Turner eventually purchased all of this, and left the NWA in the early 1990s so the company was just known as "WCW" up until purchased by Vince McMahon where it became a subsidiary of WWE.
From what I remember here is the order of the collapse of the territories and the formation of the "two party system" WWF/WCW.
This is not exact but to the best of my memory it happened like this.
1. The WWF started their expansion
2. The NWA got together and started to swap their bigger stars more frequantly between, Georgia, Florida, and Mid Atlantic due to their close proxiemety. St Louis and Central States were also sharing talent already with these areas as well.
3. Georgia and Memphis breifly alligned although they still ran seperate tv
4. The AWA and the NWA southern promotions formed Pro Wrestling USA and tried to compete with WWF, this did not last long.
5. Several territories died, like WWA, the Califonia territories, Southwest, Amarillo, and Big Time.
6. The Briscos sold their Georgia WTBS slot to McMahon
7. JCP came in and rescued the WTBS show for NWA and forged an alliance with Georgia
8. Georgia and Mid Atlantic merged although for a while Mid Atlantic still ran their own shows in their area.
9. St Louis and Central States closed shop.
10. Florida, Mid South, WCCW, Pacific Northwest, Contenintal, and Memphis all still maintained their own shows and business as usual although Florida was still loaning and borrowing talent from the new JCP/Georgia alliance.
11. Mid South became UWF
12. CWA became USWA
13. WCCW withdrew from the NWA
14. UWF merged with JCP
15. The JCP alliance left the NWA officially and became WCW
16. Florida still maintained it's seperate status as a traditional territory and member of the NWA
17. Continintal folded as a major territory taking their product mainly to the Gulf Coast and becoming more of an independent.
18. AWA, USWA, and WCCW tried to merge but it failed immediatly
19. Florida folded officially only leaving a small idnependent promotion to fill the void.
20. Smokey Mountain tried to fill the void left by Contenital.
21. USWA bought out WCCW
21. Pacific Northwest folded
22. AWA folded
23. USWA deserted the Texas end of their territory
24. GWF tried to capitalize on the death of WCCW
25. Eastern Championship wrestling, an indy promotion evolves into ECW.
26. USWA is bought out by WWF making it a developmental territory, but allowing it to keep it's own television, and older stars.
27. Smokey Mountain folded
28. GWF folds
29. The NWA tries to rebuild using these indy promotions.
30. USWA struggles and folds after trying again under a new name.
31. Every traditional territorial promotion is dead.
---OFFICIAL DEATH OF THE TERRITORIES---
Only WCW and WWF remain as the non-indy promotions (although some would argue ECW was more than an indy by this point)