Other Discworld Locations

Here are a few that the PCs would likely have at least heard of.

Sto Plains
The Sto Plains largely consist of cabbage fields. The river Ankh lazily meanders through the plains, gathering silt and eventually going through Ankh-Morpork, then to the Circle Sea.

Quirm
This is a smaller city than Ankh-Morpork. Its most famous item is its floral clock for which different flowers open for different hours of the day. Many people in Ankh-Morpork view Quirm as "a quaint nice place."
Ramtop Mountains
Lancre
People hear stories about Lancre and surrounding area, particularly when it comes to family trees. It's located high in the Ramtop mountains, where it seems that space wasn't big enough for the surrounding geography and got folded somehow. Lancre is run by King Verance and Queen Magrat, who are trying to bring the town into the Century of the Fruitbat. The castle is generally falling apart in bits, particularly parts which aren't in use. People here tend sheep and goats and the like, and maybe do a bit of farming on the parts of the mountain which aren't quite as pointy.

Uberwald
People also hear stories about Uberwald, but these are darker, more sinister stories. Everyone knows that the place abounds with vampires, werewolves, and strange dark castles. There seems to be a lot of lightning and stormy nights in this locale, making it prime Mad Scientist country as well.

Klatch
The people of Ankh-Morpork generally consider Klatchians to be uncouth, foul, mean-spirited, uncivilized people. This is of course not particularly true, or at least not moreso than the citizens of Ankh-Morpork are any of those things. Any PCs from this area will know other things. [Generally Arabic-ish in a sense]

Ephebe, Tsort and Djelibeybi
Ephebe and Tsort are divided by the Djel River, along which is the very narrow country of Djelibeybi (Sorta like Egypt, but with more pyramids). Queen Ptraci rules in Djelibeybi now. Tsort also has pyramids, and tends to borrow culture from its nearby desert countries. It also has a lasting feud with Ephebe, which only the fact that Djelibeybi is in the way prevents outright war (trade between the two happens in the neutral country of Djelibeybi). Ephebe is a country of philosophers (when they aren't at war with Tsort).

Counterweight Continent
The only thing that most people know about the Counterweight Continent is that it balances the load of the Disc on the back of the four elephants which ride upon Great A'Tuin the star turtle. Most people don't know where it is. It is definitely Foreign Lands, and hence worthy of suspicion.