SAMCRO is an acronym for Sons of Anarchy Motorcycle Club, Redwood Original charter. That is referring to the specific founding charter that occupies Charming, California. Every other sect of Sons of Anarchy has their own charter, therefore SAMCRO is only found in Charming.
It's isn't Sam Crow.. It's an easy mistake to make.. Even I made it when I first started watching the show, even the subtitles on Netflix say "Sam Crow" anyway... It's SAMCRO (as you should see below) it stands for Sons of Anarchy Motorcycle Club Redwood Original.. Redwood being the charters name because J.T. Thought that charming was a weak name for a charter of a biker club