Q. What is it supposed to be on the show? A. A parking lot, next to a hamburger stand. 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 10, of Season 6, "Ricochet Rabbit". After being rejected by Debra, Quinn has been slowly getting worse as the season progresses, losing himself in booze. In this brief scene, a hungover Quinn is asleep in the passenger seat of his car, his feet dangling out the car window. He's parked next to some place with a "Happy Hour" sign, there are empty beer bottles strewn about, and one of his shoes is lying on the ground. Suddenly, automatic sprinklers come on and drench him.  At the same time, his phone starts to ring. Quinn wakes up in a hurry, disoriented.  He answers the phone, stumbles out the door, retrieves his soaking wet shoe from the wet lawn, and walks around to the driver's side. Q. What is it actually in real life? A. A parking lot. Q. Where can I find it in real life?

This is the parking lot of the Highland Park Senior Citizens Center, at 6152 N. Figueroa Street, in the Highland Park section of Los Angeles.

But this scene was shot in the northeast corner of the parking lot, which faces York Street (to the north), not Figueroa.

The place seen next door, with the "Happy Hour" sign, is actually not a bar at all.  It's a fast food place called Classic Burgers, located at 6240 York Blvd.  It borders on the park that contains the Senior Center.

The sprinklers, which wake Quinn up, were fake, installed for the production.  And so is the grass where he loses his shoe (they put in sod on a planter/divider that is usually just bare dirt).

This is the same seniors center where they filmed the earlier scene of Travis at the Internet Cafe.

And in Episode 9, they used the center's south parking lot here for the scene where LaGuerta talked to Matthews in a parked car.

The senior center is right next door to Travis's church, which has been a central location all year.

The church is right around from the cougar's house.

And less than half a mile away, to the southwest, are two other Season 6 locations: the barber shop (where Dexter killed the gang leader, Julio), and the fake coffee stand where Debra told Angel about her promotion.

(Considering that Dexter had never filmed in Highland Park before, they certainly did a lot of it this season.)

Here is a Google StreetView of both the lot and Classic Burgers.
(The red X marks the spot where Quinn was parked.)

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

A.  In previous seasons, I've usually had to hunt down the locations after viewing the episodes, using clues from the various scenes.  By the 6th season, though, I'd 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 aired, I already knew most (but not all) of the filming locations, and only needed to watch the episodes and match up the scenes with the correct locations.

This group of helpful fans includes Kerry, Rick, Ellen, Susan, Jason, Elaine, Joel, Julie, Geoff, Jeff, Jen, and others. My thanks to all of them.

Rick tipped me to this one, and I was able to confirm it via aerial photos and StreetView.  That 99-Cents store across the street is hard to miss.  (Thanks, Rick!)