Which preposition to use with gua

on Occurrences 2%

The king answered:"I have a place, convenient for fish and wood, beside Slieve Gua on the bank of the Nemh

in Occurrences 1%

On yet another occasion Declan was in his own regiontravelling over Slieve Gua in the Decies, when his horse from some cause got lame

Which preposition to use with  gua