Most illegal drugs in the US are produced abroad and enter through Mexico and the broader Mexico/Central America corridor, while many prescription and some cannabis supplies are produced domestically or rely on foreign ingredients. Different drugs have different “main” source regions, but Mexico and the Andean countries (Colombia, Peru, Bolivia) dominate the external supply for the US market.

Big picture: where drugs come from

  • Illegal drugs overall : US law‑enforcement and research sources consistently point to Mexican cartels as the primary suppliers of imported illegal drugs into the US, operating distribution networks in hundreds of US cities. These groups move cocaine, heroin, methamphetamine, and increasingly synthetic opioids like fentanyl across the southwest border.
  • Domestic vs foreign : While a large share of traditional illicit drugs is produced abroad, a significant portion of the US drug problem comes from substances made in or heavily tied to the US itself, especially prescription opioids and domestically grown cannabis.

By drug type

Heroin and synthetic opioids

  • Heroin : US officials estimate that roughly 90–94% of the heroin consumed in the US comes from Mexico , with most of the remaining small share from Asia (especially Afghanistan) and a tiny fraction from Colombia. Central America’s role for heroin is described as marginal compared with direct flows from Mexico.
  • Fentanyl and other synthetics : Fentanyl often reaches the US either as finished product or as precursor chemicals routed through Mexico from manufacturing hubs like China , before being pressed into pills or mixed with other drugs for the US market.

Cocaine

  • Production : Most of the world’s cocaine—including that consumed in the US—comes from the Andean region: Colombia, Peru, and Bolivia.
  • Route to the US : About 90% of cocaine trafficked to the US transits through the Mexico/Central America corridor , even though it is not produced there.

Methamphetamine and other lab drugs

  • Methamphetamine : Large quantities come from Mexico , where high‑capacity “superlabs” produce meth for export to the US. Smaller‑scale domestic labs still exist in the US but represent a much smaller share than in the past as imports from Mexico have grown.
  • MDMA/ecstasy and similar synthetics : These tend to be manufactured in various foreign labs (historically parts of Europe and Canada) and then smuggled in, though there can be domestic production as well.

Cannabis and prescription drugs

  • Cannabis : US marijuana has a mixed origin. Estimates have indicated that up to around two‑thirds of marijuana used in the US has at times come from Mexico , with the rest from domestic growers and other sources. As more US states legalize and regulate cannabis, domestic production’s share has grown, reducing some dependence on Mexican marijuana.
  • Prescription drugs : Many of the most misused prescription medications (especially opioid painkillers) are manufactured in the US as legal pharmaceuticals, then diverted or misused. However, the underlying active ingredients for many prescription drugs taken in the US are now “overwhelmingly and increasingly” produced overseas, especially in India and China , even when the finished pills are made for the US market.

How they enter the US

  • Southwest land border : The primary entry point for imported illegal drugs is the US–Mexico border, using cars, trucks, tunnels, and people crossing at legal ports of entry.
  • Maritime and air routes : Cocaine and other drugs also move via sea routes through the Caribbean and Eastern Pacific, and by air from South America or via Central America and Mexico.
  • Legal supply chains : For prescription drugs and their ingredients, foreign factories ship through legal trade channels, with the products entering the regulated pharmaceutical supply chain before some are diverted into illegal use.

TL;DR: When people ask “where do most drugs in the US come from,” the short, honest answer is:

  • For illegal street drugs : mainly Mexico (as producer and transit hub), plus Colombia/Peru/Bolivia for cocaine and Asia for some heroin and synthetic components.
  • For prescription drugs : finished pills often made in the US or US‑linked factories, but with key ingredients increasingly manufactured in India and China.

Information gathered from public forums or data available on the internet and portrayed here.