I use a geochart same like this link jsfiddle.net code . I use only one parameter City or country for data-set in geochart , I am unable to change his default data fill region color .
I want to change only circle color they are currently #267114 some thing like green .
Better you can give the full information (OR) Check with this site, https://developers.google.com/chart/interactive/docs/gallery/geochart
var options = { defaultColor: '#F9CB1C' }
It's not in the documentation for some reason. #hth