Arapaho National Forest is a National Forest located in north-central Colorado, United States. The facility is managed jointly with the Roosevelt National Forest and the Pawnee National Grassland from the United States Forest Service office in Fort Collins, Colorado. The combined facility of 1,730,603 acres (2,704.07 sq mi, or 7,420.35 km²) is denoted as ARP (Arapaho, Roosevelt, Pawnee) by the Forest Service.