The board approved the $4.4 billion Sterling Ranch project after months of public hearings.
Supporters say the new project will bring in many jobs because part of the development includes a new town center and other businesses.
The development will also have 12,000 homes and apartments. Supporters say these homes are needed because surrounding neighborhoods are nearly built out.
The 3,400-acre community will be surrounded by Highlands Ranch, Littleton, Roxborough Village and Chatfield Reservoir.
Opponents of the plan say it will bring in more traffic and too many houses to the virtually untouched land in that area.
Another major concern was how to bring water to the community, and if it would take water away from the surrounding areas.
(KUSA-TV © 2011 Multimedia Holdings Corporation)