The Halo Waypoint website posted this image which details what is included with the shipment of Halo 4.
The image reads:
Ten maps might sound a bit low, but in response to a question on Neogaf, Frankie clarifies that the ten are “only referring to non-forge maps/environments”
Does this mean we can expect another forge world similar to Halo Reach’s? Reach multiplayer included dozens of custom forge maps making the gameplay stay fresh over the months.
The only downfall to the forge maps in Reach is that since all the maps had similar environments and colors, new forge maps became mundane. It is unclear for now what is in store for Halo 4 forge, but by Frankie’s response we know that they are again making map forging a large part of multiplayer.
Previously announced were the 9 DLC maps that are set to be released in the months following the release of Halo 4.