Which preposition to use with yang

in Occurrences 1%

His surname, they tell us, was Kung, and he was a native of Wu-yang in P'ing-yang, which is still the name of a large department in Shan-hsî.

on Occurrences 1%

I am anchored off the mouth of the river Han, which separates Hankow and Han-yang on the left bank of the Yangtze.

Which preposition to use with  yang