How & why did Gobblers Knob get to be the location of groundhog's day?? And Punxsutawney PA??? There must be one heck of a story behind this

This would take too long to answer here, but it is well documented at Gobbler's Knob itself as well as online.

There is a sign in the pictures showing different locations around the area of Gobbler's Knob that explains how in 1899, it was started in the location and based on an older Christian-based tradition.

What he said.