Narrowleaf willow is a species of willow native to most of North America except for the southeast and far north, occurring from Alaska east to New Brunswick, and south to northern Mexico.
This willow has many uses for Native Americans; the branches are used as flexible poles and building materials, the smaller twigs are used to make baskets, the bark is made into cord and string, and the bark and leaves have several medicinal uses. The Zuni people take an infusion of the bark for coughs and sore throats.
The foliage is browsed by livestock.
The male flowers provide pollen for bees. It is a larval host to the California hairstreak, Lorquin's admiral, mourning cloak, sylvan hairstreak, and tiger swallowtail.