Yukon–Koyukuk Census Area ( ) is a census area in the U.S. state of Alaska. As of the 2020 census, the population was 5,343, down from 5,588 in 2010. With an area of , it is the largest of any county or county-equivalent in the United States. While slightly larger than the entire state of Montana, the census area only consists of 22.2% of Alaska's total area. It is part of the unorganized borough of Alaska and therefore has no borough seat. Its largest communities are the cities of Galena, in the west, and Fort Yukon, in the northeast.
Geography
According to the U.S. Census Bureau, the census area has , of which is land and (1.6%) is water. The area is slightly larger than the entire U.S. state of Montana, itself the fourth largest state, or the country of Japan, and makes up slightly more than 1/5 of the state of Alaska. The area is bigger than 47 of the other 49 states, with only California and Texas being bigger. Its population density, at , is the lowest in the United States.
Adjacent boroughs and census areas
- North Slope Borough, Alaska – north
- Southeast Fairbanks Census Area, Alaska – southeast
- Fairbanks North Star Borough, Alaska – southeast
- Denali Borough, Alaska – southeast
- Matanuska-Susitna Borough, Alaska – south
- Bethel Census Area, Alaska – south
- Kusilvak Census Area, Alaska – west
- Nome Census Area, Alaska – west
- Northwest Arctic Borough, Alaska – northwest
- Yukon Territory, Canada – east
National protected areas
- Arctic National Wildlife Refuge (part)
- Mollie Beattie Wilderness (part)
- Gates of the Arctic National Park and Preserve (part)
- Gates of the Arctic Wilderness (part)
- Innoko National Wildlife Refuge
- Innoko Wilderness
- Kanuti National Wildlife Refuge
- Koyukuk National Wildlife Refuge (part)
- Koyukuk Wilderness (part)
- Noatak National Preserve
- Nowitna National Wildlife Refuge
- Selawik National Wildlife Refuge (part)
- Selawik Wilderness (part)
- Steese National Conservation Area
- White Mountains National Recreation Area
- Yukon–Charley Rivers National Preserve (part)
- Yukon Flats National Wildlife Refuge