Crater Rim, found south east of Freedom City through Slagtown is a dangerous area populated by vicious chukkas and occasionally hostile rednecks. Wild beefalo roam the crater, shitting heedlessly, while armordillos stand around doing whatever armordillos do. Points of interest include the billygoat mutation spot and the BlastArms ammunition shop.
To the East lies Maas Neotek.
A detailed map with descriptions can be found here.