DENVER — Colorado officials submitted eight sites to Amazon on Wednesday in hopes of attracting a new headquarters to the state.

Colorado’s bid encompasses urban and suburban locations, although Metro Denver Economic Development Corporation, the group coordinating the effort, is not releasing the information in the bid to the public.

Colorado’s decision not to disclose the details in the proposal is a departure from other cities and states.

Earlier this week, sources said three sites have emerged as favorites in the proposal, but officials Wednesday said all eight sites are being marketed equally.

Sources previously have indicated that tax incentives are a part of the proposal, but they will not exceed offers from other states.

Instead, an emphasis was placed on Colorado’s high quality of life and is heavily marketed in the pitch.

Sources close to the proposal say three areas, while vague in nature, are in the proposal. Officials say the bid identifies specific parcels of land, not generic areas.

Land near Denver International Airport

This location is popular because of its proximity to Denver’s airport as well as RTD A Line train accessibility.

There is also ample room for growth for the estimated $5 billion facility, which is expected to house 50,000 employees.

Land near U.S. 36 and Northwest Parkway

This location in Louisville is popular because it is close to the airport by the Northwest Parkway and is currently zoned for commercial use.

It is also within a half-hour of downtown Denver and Boulder.

Land near E-470 in Douglas County

This is a popular location south of the city with access to many neighborhoods and high-performing schools.

Now that bids for Amazon’s nationwide HQ2 competition are submitted, the company is expected to announce its choice next year.

The Metro Denver Economic Development Corporation said it believed making it bid proposal public would jeopardize its bid’s chances.