Imperial National Wildlife Refuge protects wildlife habitat along 30 miles of the lower Colorado River in Arizona and California, including the last unchannelized section before the river enters Mexico. The river and its associated backwater lakes and wetlands are a green oasis, contrasting with the surrounding desert mountains. More than 15,000 acres of Imperial National Wildlfie Refuge is designated as wilderness. Wilderness is protected to ensure that nature, not people is the primary influence on this quiet, scenic place.