During the 80s and 90s, jamaicans groups were probably some of the toughest and strongest groups in the criminal world.
They were present in many cities of the US, like NYC, Miami, philly and others. They also habe a great presence in Canada, mainly in Toronto.
They were also strong in England, were they were called Yardies.

The Shower Posse is probably the most well known of the jamaican posses. They made war with many african american groups in the US. The war between the Shower Posse and the Junior Black Mafia in Philadelphia, is well known.