Q. What is it supposed to be on the show? A. A rooftop and a public street. Q. Where is it supposed to be on the show? A. Somewhere in Miami. Q. When did we see it on the show? A. In Episode 4, of Season 7, "Run". Dexter has been captured by crazed serial killer Ray Speltzer, who then begins chasing Dexter through a maze - while dressed as a horned bull and carrying an axe. Since Speltzer attempts to force Dexter to flee to a lower floors in the maze, Dexter decides to change things by heading up instead. They wind up on a rooftop in a bad part of town, atop what looks like a brick warehouse. Dexter manages to escape, making it down to the street and catching a ride on a passing truck. but he realizes that Speltzer now knows what he looks like.  He decides he will have to get his son, Harrison, out of harm's way before he goes after Speltzer again. Q. What is it actually in real life? A. A rooftop and a public street. Q. Where can I find it in real life? A. This scene was shot on the rooftop of what is known as Willow Studios, in the warehouse district of downtown Los Angeles.  The address is 1333 Willow Street. It consists of a number of old brick buildings (no doubt former warehouse or industrial properties) that are now being used for filming. Hollywood films a lot down in this rough part of town, for its authentic look, and it seems like half of the old buildings there have a sign out front advertising them as a filming location. When Dexter emerges onto a brick courtyard of sorts (soon followed by Speltzer), he is on the roof of Willow Studios. (The camera is looking east.) You can see the exact spot here. The final moments of this chase scene, where Dexter hops a truck and rides away to safety, was shot down on Willow Street, between Santa Fe Avenue & Mateo Ave. (The truck is heading east on Willow, towards Mateo.) Here is a matching view of the street. (Note the same red awning on one storefront.) Speltzer is seen standing on the roof of Willow Studios, next to the towering electrical poles seen here.

Here is a Google StreetView of the building:

Q. How the heck did you figure out where it was?

A.  In the early seasons, I usually had to hunt down the locations after viewing the episodes, using clues from the various scenes.  By the now, though, I've developed a small group of fans, spies & tipsters who kept an eye out for Dexter filming in their neighborhoods, and would let me know in advance when something was about to film there.

Between those reports, my own personal reconnaissance around town, and a few new resources I discovered, by the time the first episode airs, I already know most (but not all) of the filming locations, and only need to watch the episodes and match up the scenes with the correct locations.

This group of helpful fans includes Rick, Ellen, Elaine, Mia, Joel, Susan, Eric, Jeff, Kerry & others. My thanks to all of them.

I'm familiar with this warehouse district. I have found many a location here, over the years, from movies to TV shows.

Once you know the place, there are certain recognizable landmarks in the area that are easy to spot.

When Dexter & Speltzer are up on the roof, you can see a few of these landmarks below them, including the Southwestern Bag Company (1380 E. 6th Street, seen in the second screenshot from the top), and a rather gigantic work of graffitti/tagging, which reads "Risk Revok Augor", and which is located just behind 581 Mateo Street (seen in the third screenshot from the top).

That tells me that the camera is looking west when we see the graffiti and is looking southwest when we see the Bag Company.  It's easy to then just draw lines to the camera position, and then confirm it via Google StreetView.