Texas

Really cool find!

It is indeed very abundant. The Panda-Stegodon fauna ranges from Southern China to Southeast Asia but I believe the most fossiliferous locations are still in the Guangxi and Guizhou provinces of Southern China.
 
Reasons for these teeth being in the caves:
1. Carried by underground waters
2. Animal seeking shelter in here but ended up getting trapped
3. Most importantly, it's difficult for these to fossilize outside, where they can be destroyed by other animals/microorganisms/weathering. Inside the caves the temperature would be quite stable and if there are less bats, there are relatively less amount of bacteria. 
Most southern Chinese caves are limestone caves, meaning that the bones get eroded but the teeth crowns are heavily calcitized and look quite awesome when placed above a flashlight.
 
And yes, GIgantopithecus is extremely rare. You could even consider the Guangxi and Guizhou provinces as places where it's most abundant. Even still, it rarely turns up.

Thank you so much! The credit all goes to my mom who carved out the silhouettes of these teeth on the black sponge background and inserted these teeth in:)

Good lord, you can just pick up handfuls??  Is there a current consensus on how all these teeth (etc) got into the caves?  Hard to see how stegodon bits are assorting with deer and pigs!   Any additional evidence on hyaenas being the primary collectors?  Water and humans always possible, and my favorite "all of the above" if you pick the right millennium.   Is Gigantopithecus rare everywhere it's known?  So many missing pieces to that puzzle.

What a nice display!  Nice finds as well

Nice one!

Not sure, I believe S. falcatus is something of a bucket taxon, perhaps S. hartwelli? I've taken to eschewing specific assignment on many of these teeth.

Falcatus? 

Beautiful tooth
 

Nice sample, permission to use it in an activity and coloring book for kids that I'm making?