"Downtown" is slang in NYC and elsewhere for heroin, as opposed to "
uptown," which is crack or cocaine. This
distinction is usually only necessary when the
dealer happens to sell both heroin and crack or cocaine.
(
Dealer's cell phone rings)
Dealer: Yeah, who's this?
Buyer: It's _______.
Dealer: What do you need?
Buyer: I need 2 downtown and 3
uptown.
Dealer: Go to 20th between Broadway and Fifth in 10 minutes.