18th st would consider itself a gang, very similar to MS13. In reality they mostly aren’t, with so many cliques spread around, it’s like an alliance of smaller gangs calling themselves 18 street. At least that’s how I see it. Some cliques having stronger ties with each other than others and some cliques being more isolated from the rest. I suppose you can consider them one of the largest gangs in the country still, but IMO they been on a heavy decline since the mid 2000s.