Supposed to be Detroit, but every license plate is "Ohio".
Most of the film takes place on January 1, New Year's Day; all of the government offices visited by Stretch and Spoon would be closed that day.
Supposed to be Detroit but in one outdoor scene you can see the outline of mountains in the background.
When main characters are in the diner for "breakfast", the TV news broadcast from the kitchen shows the announcer doing station identification as "KMT" ... they're supposed to be in Detroit, east of the Mississippi River, where station IDs start with a "W" ... stations west of the Mississippi start w/ a "K".
When Spoon and Stretch are running from the drug dealers, the mic is reflected in a window.