Hi! I know this question is old, but it might help other users looking for the same.
I developed a map generator that creates simple maps, with country outlines, where you can add markers that can have tooltips and perform actions when clicked. You can have a map of the world, a specific continent or even a specific country divided by regions.
I wrote a quick tutorial on how it works and how to embed it on squarespace: http://cmoreira.net/blog/how-to-add-a-world-map-to-your-squarespace-website/
It's a premium script, but it comes with support and the embed code is compatible with Squarespace, from the tests I performed.
Hope it helps.