Adding Shipping Surcharges To Countries?

If we only use one shipping carrier such as UPS for both our US and Canadian shipping; is there a way to add shipping surcharges only when shipping the US for example?

You do this via locations. But it's a different rate, not a surcharge. It you want a conditional surcharge it takes a small amount of custom code.

Please have a look

CS-Cart Documentation — CS-Cart 4.15.x documentation

You can mix manual rates with on-line shipping processors