Cut Halo 4 levels

During the development of Halo 4, company Digital Extremes was contracted by 343 Industries to help with the production of the game's DLC map packs. A number of map ideas and concepts were pitched to 343 but went unused, and have since been released online.

Arrowhead
"Arrowhead" was one map concepted, and evidently would have taken place in or around a UNSC facility embedded in a cliffside, though no other details are known.

Covenant underwater technology
This map was designed to focus on underwater Covenant technology.

Genessis
Identified in a series of concept art uploads all titled, this map has a similar theme to the release map Vortex, set in a Forerunner installation in a desert wasteland. In the distance, a Forerunner Keyship can be seen. It is unknown if this pitch has any relation to the planet Genesis featured in Halo 5: Guardians.

Last Resort remake
One map concept shown involves a paintover of the sniper tower area of the Halo 3 map Last Resort. Its filename,, suggests it was intended to be a Last Resort remake. Notably, the map was later realised in Halo 2: Anniversary's multiplayer as Stonetown.

Narrows remake
One concept pitched to 343 involved a remake of the Halo 3 multiplayer map Narrows, redressed in a human architectural aesthetic..

ONI Bog
Concept art for the map suggests it would have had a similar theme and tone to the map Abandon, though it is unknown if the two maps are one and the same, or simply similar.

Other DLC map concepts
Some callout sheets for individual map props have been posted online, of which tie to no particular known map.