Grand County’s lakes are now free of ice and are open. All boats launching and exiting our lakes must comply with mandatory Aquatic Nuisance Species (ANS) Inspections to keep our lakes free of invasive Quagga and Zebra Mussels.

The hours of inspection station operations are listed below:

Grand Lake:

Open/Close Date: May 17 – November 17

Hours of Operation:

Grand Lake Public Ramp 6 am – 8 pm daily

Lake Granby:

Open/Close Date: April 15 – November 17

Hours of Operation:

Stillwater Ramp: 6 am – 8 pm daily

Sunset Ramp: 6 am – 8 pm daily

Special Considerations: Boaters using Arapahoe Bay on Lake Granby are expected to get their inspection at the Sunset Boat Ramp

Private Service Providers: Beacon Landing Marina (on Lake Granby) 1026 Co Rd 64, Grand Lake (970) 627-3671. Select privately operated inspection and decontamination services are fee-based and prices may vary among providers. Contact vendor for pricing and details.  

Shadow Mountain:

Open/Close Date: May 17 – September 30

Hours of Operation:

Green Ridge Boat Ramp 6 am – 8 pm daily

Restrictions: Hilltop Boat Ramp on Shadow Mountain Reservoir will remain closed to trailered motorized watercraft per the order from the United States Forest Service (USFS)

Restrictions: Ramps are closed to launching when inspectors are not present. For more information, contact US Forest Service (970) 887-4100.

NEW this year: Motorboats and sailboats must have an ANS Stamp prior to launching in Colorado in 2019

Boat owners are required to purchase the ANS Stamp and operators must retain proof of purchase (electronic or printed receipt) on his or her person, the motorboat or sailboat, when operating the vessel (C.R.S. 33-10.5-104.5).

Motorboats and Sailboats from Colorado – $25.00

Colorado residents will purchase the ANS stamp at the time of registration. If you register/renew your vessel online or via a registration renewal postcard, the cost of the ANS stamp appears as part of your total amount due. You do NOT need to manually add another $25 to your payment for an ANS Stamp.​​

Residents with motorboats or sailboats documented by the U.S. Coast Guard or otherwise exempt from in-state registration can purchase purchase their ANS stamp online at​, or at any CPW office or sales location​ beginning January 1, 2019​. ​

​​Motorboats and Sailboats from Another State – $50.00

Non-residents can purchase their ANS stamp online​, or at any CPW office or sales location​  beginning January 1, 2019​. ​

Funding contributes to prevention and management of ANS in the state. ​​​​​​​​​​​​​​​​