Q. What is it supposed to be on the show?

A. It's unclear, but it looks like some sort of commercial or visitors area, where there is at least one information booth set up to hand out flyers to  passersby .  

 
Q. Where is it supposed to be on the show?

A.  Somewhere in  New York City.

Q. When did we see it on the show?

A. In Episode 6 of Season One of Resurrection.

We first see Harrison wandering past what appears to be some sort of playground, when he comes across an information booth from New York University (NYU).
 
Having just gotten his GED, he is thinking about the possibility of going to college, so he picks up a flyer being handed out by the people in the booth.

But his enthusiasm fades when he looks at the flyer and sees just how much tuition costs.

Q. What is it actually in real life?

A. A touristy historic/commercial area near the harbor.

Q. Where can I find it in real life?

A.  This scene was filmed in an area of Lower New York known as the Seaport, the same area where they filmed the scene of Dexter stalking Gareth at a bookstore. (They doubtlessly filmed both scenes around the same time.)   

When we first see Harrison, he is  walking past a black wrought-iron fence, next to what looks like some sort of playground.  

In this scene he is walking northwest up a pedestrian-only walkway that runs from South Street (on the south) to Front Street (on the north), just east of  John Street (the path lies between the east side of the playground and west side of the Schermerhorn Row block. 
 
The camera is looking south/southeast, while Harrison is walking northwest past what is called the Imagination Playground, a colorful park playground that runs along the entire east side of this path (and maps to 159 John Street). 
 
When he spots the NYU booth, Harrison has just reached the intersection where two pedestrian-only streets meet at the Seaport: this John Street pedestrian path and Front Street.  ( John Street runs east / west, while Front Street runs north / south. )

The NYU booth itself appears to have been set up on the north side of rusty he Front Street walkway, just in front of two storefronts: Black Gotham Experience and (the now-closed)  Xpizza, which is located just a short walk to the right (northeast) of where John Street meets Front Street.  
 
( What first appears to be a row of gray storefronts along Front Street is actually just the ground floor (and back side) of a modern 35-floor skyscraper known as One Seaport Plaza, the front of which faces Water Street.  Ironically, it is just a few steps south of the historic Schermerhorn Row building, an 1812 brick structure which houses the South Street Seaport Museum, as well as the bookstore where Dexter meets Gareth. )

The booth's location is also just 140 feet northwest of the tall ships docked at Pier 16 by the South Street Seaport Museum. 
The museum has five historic vessels docked permanently, including the Wavertree, a tall ship (and a National Historic Landmark) built in 1885, which can be briefly glimpsed in the distance behind Harrison when he's walking on John St. near the playground.   
 
As a Southern California native, I was unfamiliar with the Seaport, but Wikipedia defines it as: “a historic area in the New York City borough of Manhattan, centered where Fulton Street meets the East River, within the Financial District of Lower Manhattan. ... includes the largest concentration of restored early 19th-century commercial buildings in the city...  renovated sailing ships, the former Fulton Fish Market, and modern tourist malls featuring food, shopping, and nightlife.”

One website offers this description: .“Located along the East River with unparalleled views of the Brooklyn Bridge and the City skyline, the Seaport is one of the most dynamic neighborhoods in New York City. The charming cobblestone streets and historic buildings that make up the City’s oldest waterfront neighborhood continue to bustle with commerce and culture; the Seaport is home to the South Street Seaport Museum as well as some of the city’s most innovative culinary, fashion and entertainment experiences that both locals and visitors can enjoy.” 
 

The Seaport district features some of the oldest buildings in Lower Manhattan, and includes the largest concentration of restored early 19th-century commercial buildings in the city, including the former Fulton Fish Market, restaurants, movie theaters, and shops.


Here is a matching StreetView of where Harrison was walking past the playground:
;
 

Here is an aerial photo of the location.  And here is a map link.


Here is a matching StreetView of where The NYU booth was set up:
( the booth was approximately where the person is standing in this image )
;


Here is an aerial photo of the location.  And here is a map link.