Grand Theft Auto 5 has a 'very big' map
Aside from speculation and rumors based off of one single trailer, we don't have any hard, factual evidence about Rockstar's highly-anticipated game Grand Theft Auto 5. Rockstar has been very limited in the information they are sharing about the game. In fact, all we really know is that GTA 5 will "head to the city of Los Santos and its surrounding hills, countryside and beaches." This was taken from the original press release in which Rockstar claimed Grand Theft Auto 5 will be their "most ambitious game" they've yet created.
This bit was further emphasized by Rockstar co-founder Dan Houser, who told Game Informer that GTA 5 will have a "very big map". Though the interview focused mostly on Max Payne 3, Game Informer attempted to pull any information they could from Houser. Unfortunately, they were unsuccessful.
"I've got to be real careful here, or they will drag me through the office and whip me with barbwire," Houser said. "I will stick to exactly what's in the press release. It's Los Santos and the surrounding countryside - and a very big map."
Given the ambitious goals set by the developers, and predictions that GTA 5 will be 2012's biggest game, it's safe to assume the map will be the largest one yet.