Apartment 4A

Apartment 4A is the primary setting in The Big Bang Theory, and is the where Sheldon and Leonard live. It is situated in an apartment complex at 2311 N. Los Robles Avenue. When viewed from the satellite photographics in "The Countdown Reflection" episode it appears to be located at 215 S Madison Ave. Due to the primary characters in the series, albeit Penny, being of the "nerd" social classification, the apartment has been dubbed as "Nerdvana" by Howard in season 1 episode 14 "The Nerdvana Annihilation".

Apartment 4A is located on the fourth floor of the building across from Apartment 4B, where Penny lives. 4A is known to be a corner apartment, being that it has windows facing outside on two sides.

Layout
The apartment has one living room, one bathroom, and two bedrooms. A hallway links the the living room to the bedrooms. The kitchen is part of the main living area.

Immediately upon entering, the wall on the right houses Sheldon and Leonard's desks and the TV. The wall ends in the kitchen part. This wall is rarely visible, being the wall that is the view into the apartment from which the episodes are filmed, and has only been shown on two occasions (one is in "The Euclid Alternative", S2E5).

The wall immediately to the left after entering the apartment has a long bookshelf that ends at a small closet, with the wall itself ending at a large window with a desk and telescope. can be seen from this window, which has been used on several occasions:
 * "The Tangerine Factor" (S1E17), Penny throws her ex-boyfriend Mike's out of it
 * "The Panty Piñata Polarization" (S2E07), Sheldon shows Penny that he hung her clothes from a outside
 * "The Einstein Approximation" (S3E14), Sheldon throws a out the window, causing the sound of car tire screeching and car horns, implying that there is a fairly large road just down the window and that Sheldon just caused an accident.
 * "The Ornithophobia Diffusion" (S5E09), a lands on the window sill outside, which upsets Sheldon

After the window, there is a corner and the hallway that leads to the bathroom, as well as Sheldon and Leonard's bedrooms. The kitchen area is a small area that has an island with rarely used s since they usually eat in the living room area. A window is located at the end of the visible wall of the kitchen area (which can be clearly seen in several kitchen area scenes, one typical instance is in "The Loobenfeld Decay", S1E10, when Toby Loobenfeld talks with Sheldon in the kitchen area). Presumbly, this window is one of the two windows (the other being the large window described above) that Sheldon has stated "creates a cross breeze" when he describes his Spot.

Sheldon, at one point in time, had painted luminous arrows on the floor pointing to the various nearest emergency exits throughout the room. He shows them to Raj in "The Roommate Transmogrification" (S4E24), but gets rid of them before "The Friendship Contraction" (S5E15) when he explains that they were "wildly ".

Production-wise, the bathroom interior, Sheldon's bedroom, and Leonard's bedroom are actually filmed on a different set than the rest of the apartment. The actual apartment set ends at a corner in the hallway immediately after the bathroom door. This is for easier filming access and better view of the actors for the studio audience.

Bathroom
The bathroom has a double bath/shower. Sheldon and Leonard have a with the  printed on it. Sheldon has placed a  there to stop his toothbrush from being infected by germs. Sheldon also has tape on the floor which serves to avoid on the mirror from, and to stop urine from getting on the floor when men use the toilet. Sheldon also has a to clean the mirror.

===Sheldon's FUck Room Sheldon's bedroom is located immediately after the bathroom. Sheldon usually keeps his bedroom locked, and rarely allows anyone inside.he fucks people here

Leonard's bedroom
Leonard's bedroom is the last room in the hallway. There is a ledge outside that runs by both bedroom windows. Sheldon uses this during "The Bozeman Reaction" to access Leonard's room because he is too paranoid to go out of his bedroom because they were burglarized earlier in the episode.

History
In "The Staircase Implementation", the story of how Leonard and Sheldon meet is revealed. Sheldon places an ad for a roommate after his former roommate named Sebastian is driven to the brink of madness from Sheldon's antics. Leonard encounters Sebastian on his way to the interview with Sheldon, and he tells Leonard to run away. Leonard is accepted by Sheldon as his new roommate and inherits Sebastian's former room, only to discover that Sebastian wrote "DIE SHELDON DIE" in red (like in a ) on the wall.

At this time, the apartment also had significantly less furniture in the living room. Sheldon's only placement was two s and s as the TV stand. Even at this point in time, Sheldon's lawn chair was placed in the exact spot that he claims later on the couch. Their first major addition in furniture to the apartment was the leather couch, in which Leonard buys for a $100 from tenants on the first floor who were moving out.

In "The Bozeman Reaction", the apartment got burglarized. Some of Sheldon and Leonard's game systems and various games were stolen. The police were also called to the apartment in "The Zarnecki Incursion", when Sheldon's World of Warcraft account was hacked.

In "The Staircase Implementation", an "apartment " is mentioned as a small blue flag with a on it of a gold lion  on a  on it. Flipping it upside down signifies that the apartment is in distress. In "The Roommate Transmogrification", Raj was given a version.

List of known items in the apartment

 * Appliances
 * (Sheldon loves his tea)
 * (destroyed by the guys' battle robot in "The Killer Robot Instability")
 * (destroyed by the guys' battle robot in "The Killer Robot Instability")
 * (destroyed by the guys' battle robot in "The Killer Robot Instability")
 * (destroyed by the guys' battle robot in "The Killer Robot Instability")
 * (destroyed by the guys' battle robot in "The Killer Robot Instability")


 * Comics
 * Batman (Leonard gives it to Sheldon in "The Bat Jar Conjecture")
 * Leonard's  (mentioned by Leonard in "The Recombination Hypothesis" but previously Stephanie supposedly threw it out in "The Vartabedian Conundrum")
 * Green Lantern lantern and ring (Sheldon brings them to a university mixer party)
 * (Raj gives them to Sheldon in "The Psychic Vortex")
 * Various s


 * Furniture
 * Glass (where the gang usually eats and plays various games on)
 * s (for the laptops and iMac near the back window)
 * Leather couch (with Sheldon's spot)


 * Gaming
 * (on back of the front door), which is never seen used in the show because, as Leonard explains in "The Itchy Brain Simulation" (S7E08), they had played dart once (obviously off the screen), and Leonard broke the window that is opposite to the door.
 * (seen in many episodes but featured in "The Rhinitis Revelation" where Leonard holds it out to a sick Sheldon)
 * : Legendary Edition Replica   (was on an end table/mini-bookcase in front of rear desk by living room window)
 * Various games
 * Video game consoles: Nintendo Entertainment System (NES), Super NES, Nintendo 64, Nintendo GameCube, Nintendo Wii, PlayStation (1-3), Xbox, Xbox 360
 * Rubik's Cube cookie jar.


 * Science-related
 * 17 Base Pair Double Helix Model molecule model
 * (in bathroom)
 * (plastic sphere on top of bookcase behind couch)
 * (on bookcase behind couch)
 * Sheldon's machine


 * Star Wars
 * Leonard's green (Leonard wields it after hearing a noise late at night in "The Big Bran Hypothesis", mocks Sheldon with it after the power goes out in "The Friendship Contraction", and Penny and Sheldon try a contest where they spin around it and then rush over to do a division problem while still dizzy in "The Re-Entry Minimization")
 * helmet (worn by Sheldon in "The Ornithophobia Diffusion" as he approaches the bird on the window ledge)
 * (on Leonard's nightstand in his bedroom first seen in "The Precious Fragmentation", a  Heroes of the Rebellion in Stormtrooper Disguise Sixth-Scale Figure and a   15-inch Pre-Painted Soft Vinyl Model; the  in Stormtrooper Disguise Sixth Scale Figure that accompanies the former has been on the bookshelf next to the apartment entryway since "The Vengeance Formulation")
 * In season 7 on the book case behind the sofa in the living room is a replica of the Yoda Lamp from The Empire Strikes Back.
 * A gollum statue on Sheldon's desk


 * Other film and television and pop culture
 *  "Longclaw" (Sheldon and Leonard buy it at the comic book store in "The Russian Rocket Reaction")
 * Various s
 * Various s


 * Technology
 * (seen in "The Pants Alternative" and "The Gorilla Experiment" )
 * s (Sheldon and Leonard originally both had XPS m1710s--Sheldon's was red--but both were stolen in "The Bozeman Reaction" and replaced with a red  M17 Nebula for Sheldon and a Dell XPS Adamo for Leonard)
 * Orca (usually hanging on the Apple iMac monitor on the desk near the rear window)
 * s (Sheldon and Leonard originally both had XPS m1710s--Sheldon's was red--but both were stolen in "The Bozeman Reaction" and replaced with a red  M17 Nebula for Sheldon and a Dell XPS Adamo for Leonard)
 * Orca (usually hanging on the Apple iMac monitor on the desk near the rear window)
 * Orca (usually hanging on the Apple iMac monitor on the desk near the rear window)


 * Miscellaneous
 * Sheldon's s (Sheldon gets an HO-guage model railroad starter set in "The Pulled Groin Extrapolation")
 * Various books and computer software on shelves
 * Leonard's (read by Amy in "The Pulled Groin Extrapolation")
 * Sheldon's and Leonard's s

See Part 7: Shedding Light on Dark Matter of the book Unraveling the Mysteries of the Big Bang Theory by George Beahm (2011, BenBella Books, ISBN 9781936661312) for more fantasy, sci-fi, pop culture, and other items mentioned on the show in general.