Multiple locations

I was wondering if longhorn can be used to distribute storage to a cluster where the nodes are in different locations within a region. What kind of limitations exists? And can longhorn do multi region?

Yes. There is no limitation in theory. But you may need to be careful that the latency between the cross-region nodes will affect the volume performance once the replicas of a volume reside in different regions.

In short, yes - you can use it to distribute.