I think to say NY=Dominicans is an over simplification.

The 2015 National Drug Threat Assessment reported that Mexican traffickers were expanding their operations to gain a larger share of Northeast markets and were now the most prominent wholesale-level heroin traffickers in the New Jersey, Philadelphia, and Washington, DC, and have greatly expanded their presence in the New York City area. Mexican organization were also said to be involved in wholesale cocaine distribution in the city. In New York City, Colombian organizations transported cocaine into the area and served as a primary source of wholesale quantities of cocaine. However, Mexican and Dominican trafficking organizations dominated the transportation of cocaine throughout the rest of New York State, limiting the role of Colombian organizations. Colombian organizations were also prominent transporters and distributors of wholesale quantities of heroin in New York City. It was also reported that Dominican traffickers were the dominant retail distributors of cocaine in the New York metropolitan area and both Colombian and Mexican TCOs relied on Dominican traffickers to assist in the transportation of heroin throughout New York, New Jersey, Pennsylvania, Connecticut, and Massachusetts. In New Jersey, Dominican traffickers handled retail-level distribution of cocaine for Colombian TCOs and also supplied local street gangs, who handled street-level distribution.