A squirrel bridge is a construction (similar to a wildlife crossing) which enables small animals, especially squirrels and martens, to safely cross busy roadways.
The bridges are a measure for wildlife management and natural habitat preservation, and serve the functions of both animal welfare and accident prevention.
The Nutty Narrows Bridge in Longview, Washington, built in 1963, is regarded as the first of its kind.
Simple rope bridge constructions, such as those in Brecht, Belgium, have cost only about 250 euros, while the bridge built in The Hague in 2013 took half a year to construct and cost 150,000–200,000 euros.
The following bridges protect the red squirrel, common in Europe, or the North American gray squirrel (either of which may be hunted as an invasive species depending on the continent).