From LEGO Batman Wiki
"Gotham City is a dark, crime-ridden city full of corruption. Batman has sworn to defend Gotham against villains and criminals." Lego Batman DS
Gotham City is a large city and home to Batman and several supervillains. It contains many famous locations such as Arkham Asylum, Gotham City Hall, and Wayne Manor. It has been the main site of almost every Batman comic, movie, television show, etc. The game is set in Gotham City. Part of the game occurs in the sewers and waterways of Gotham with Killer Croc as a character/enemy.