While Asian countries historically have fed European and American markets, virtually all heroin produced in South and Central America is destined for the US.
Over the last decade, we've seen a dramatic shift in the heroin trade; South American and to a lesser extent Mexican suppliers, traditionally known for their cocaine and commercial cannabis, have increased poppy cultivation and heroin production, and with lower prices have taken over the US market with white and brown powder and tar heroin.
In the northeast and along the east coast, high purity South American powder dominates the market. South American heroin is the most common product everywhere east of the Mississippi, and has the highest street level purity on average (especially on the east coast), followed by SE and SW Asian heroin. New York City is the country's major heroin hub, and feeds markets throughout the northeast and new england area. Distribution in the east and northeast is managed often by gangs/groups of Dominican Nationals. Aside from NYC, Miami and Chicago supply cities of the southeast and midwest, respectively. . The heroin available in non metropolitan areas generally originates from whichever of these cities is closest.