Epilobium nivium, commonly known as the Snow Mountain willowherb, is a perennial subshrub endemic to the Coast Range Mountains of Northern California. It was originally described based upon a collection from Snow Mountain. Although first described in 1892, as of 2019 the species is known from fewer than 20 small occurrences spread throughout high elevation sites across Colusa, Glenn, Lake, Mendocino, Tehama, and Trinity counties. The plant has bee-pollinated flowers and a growth form suggestive of a desert species.