Inthanon Mountian is one physical feature of Thailand. This mountain is very well known all over Thailand.
The Khorat Plateau is another physical feature of thailand. This Plateau is just a big flat with scattered trees and trees that are very close together.
The last physical feature of Thailand is the big plain in the center of the country. This plain covers much of the center of Thailand, hence the name central plain. I highly recommend you see all these things as soon as possible.