Tin City is located somewhere in the Tiberian Wastelands. It is named as such because it is home to one of the last remnants of the heavily mutated Forgotten. Two TCN nodes are located here to clear Tin City of Tiberium as well as some AA control towers.
Two of the missions in Tiberian Twilight take place here. Chronologically, the Nod mission The Harder They Fall came first as Kane's faithful forces shot down Colonel James's GST Tzadik as it flew over Tin City. The GDI mission Transport Down immediately takes place afterwards as James sent her GDI forces and crew to capture the two TCN nodes and repair the GST. The latter mission had GDI pitted against Nod and the Forgotten, who viewed the GDI presence as a threat to their survival. GDI had either wiped all the Forgotten present or made a pact with them to assist James in holding off the Nod forces while the GST was being repaired.