One of my favorite series of all time is the Pelbar Cycle by Paul O. Williams.
1. The Breaking of Northwall (1980)
2. The Ends of the Circle (1981)
3. The Dome In the Forest (1981)
4. The Fall of the Shell (1982)
5. An Ambush of Shadows (1983)
6. The Song of the Axe (1984)
7. The Sword of Forbearance (1985)

It takes place about 1000 years after the fall of civilization (I forget what the disaster was exactly), and it’s very interesting to see how the societies of that time descended from the survivors of the cataclysm.