Boating at Eleven Mile State Park means a boat inspection for invasive species

Eleven Mile State Park, in South Park in Park County, surrounds a large reservoir that is popular for boating and fishing. If you bring a trailered boat, there is a step before you can put it in the water: an aquatic nuisance species, or ANS, inspection at the boat ramp.

Colorado checks boats to keep harmful invasive species from spreading between waters. Trailered boats must be inspected before launching and again before leaving, and they launch only at designated ramps. Small craft that are both hand-launched and human-powered, like kayaks and paddleboards, are generally exempt, but a motorized or trailered boat also needs current registration and an ANS stamp. If a boat is found carrying mud, plants, or water that could spread species, it must be cleaned before it goes in.

This is not a formality here. In October 2025, an inspection at Eleven Mile intercepted adult zebra mussels on an arriving boat and stopped them before launch, which is exactly why these checks matter. Cleaning, draining, and drying your boat between waters protects this lake and the next one.

Inspections run within set hours during the boating season, so plan for the wait. Check the current boating rules, inspection hours, and ANS requirements for Eleven Mile State Park with Colorado Parks and Wildlife before you launch.