Ravaged Hamlets are groups of destroyed buildings dotted around Bast (Zone). Presumably, these small settlements used to belong to the United Cities but were sacked by Holy Nation during their aggression towards the United Cities in the Bast campaign.
Another closely related building, the Farm Ruins located in Okran's Valley, is similarly a small settlement that was presumably sacked by United Cities during their aggression against The Holy Nation, whose offensive has since failed and been pushed back to Bast.
There are in total 9 Ravaged Hamlets in Bast.