The capital city, Belverus, is in the western part of the kingdom on the main road to Aquilonia. This highway, the Road of Kings, continues eastward to the vicinity of the eastern Nemedian border, then drops into Corinthia and eventually crosses Zamora and the Eastern Desert.
East and west of Belverus are rich croplands and orchards. Northwestern baronies protect the borderlands between the Border Kingdoms and Nemedia proper as far as the Great Salt Marsh. The north-flowing Yellow River marks the heavily forested eastern border between Nemedia and Brythunia, emptying into the Salt Marsh. Two other rivers, the Rhyl and the Urlaub drain interior Nemedia. Most of the Nemedian rivers have basin-style drainage into the Salt Marsh.
Nemedia is anciently a part of Acheron. People of the Nemedian hills boast of their Acheronian blood. Invading Hybori destroyed Acheron, and it seems likely that Nemedia became the first of the Hyborian kingdoms. The elephant-being from Yag mentions it first among the new Hyborian nations.
Nemedia waged intermittent war with Aquilonia for centuries, but its western neighbor never made much headway against it. Its emblem is a scarlet dragon. Nemedia has a long tradition of scholarship, perhaps an Acheronian heritage.
References: Hyborian Age I-II, Tower of the Elephant, God in the Bowl, Queen of the Black Coast, Hour of the Dragon, Conan the Great, et al.