Hi!
We have an example with US states
https://demo.zoomcharts.com/geo-chart/examples/charts-on-charts/piechart-on-geochart.html
It uses shapes from this file:
https://zoomcharts.com/dvsl/data/geo-chart/states.json
You can download and use it if it suits your needs.
These shapes can be found on the internet. There are various versions of world country shapes and US state, county shapes.
One of the source for world country shapes can be found here:
Also you can try these US state shapes:
http://eric.clst.org/Stuff/USGeoJSON
But please note that shape precision can vary and is not related to ZoomCharts.