The People's Militia was originally a volunteer military organization based in Westfall,

A protector of the people.
who's goal was to defeat the Defias Brotherhood. They were founded by Gryan Stoutmantle because Stormwind seemed to have abandoned them. While they acted primairily out of the Sentinel Tower on Sentinel Hill, members of the Militia often patrolled the roads of Westfall.
They were mostly disbanded when they reformed as the Westfall Brigade.