Willamette National Forest: Three Sisters Wilderness area—National Forest Service information about camping, climbing, and trails within the Three Sisters Wilderness – 286,708 acres with approximately 420 km (260 mi) of trails including a portion of the Pacific Crest Trail.
Pacific Northwest Seismic Network's Three Sisters Website—The premier source for information about seismic activity around Three Sisters.
Oregon Department of Geology and Mineral Industries (DOGAMI)—State of Oregon geology information. Access to maps, LIDAR data, and field trip guides are available for Three Sisters and other regions within the state of Oregon.
Discover Your Northwest—A good source of books, maps, and other information for wilderness areas within the state of Oregon. Search Three Sisters for region-specific resources.
Summit Post Climbing Information for Three Sisters Wilderness—A resource for technical mountaineering information supported by a community of outdoor enthusiasts who share information and stories about backpacking, rock climbing, hiking, and camping.