Dee Wright Observatory stands at an observation point near a notable combination of historical and geological features developed under the Willamette National Forest and built by Civilian Conservation Corps Company 927. To the south, the Three Sisters bear 17 glaciers covering 2257 acres, the largest glacial area so far south in the United States. The surrounding lava fields cover 65 square miles and are among the youngest in the country, while land islands to the west are older earth surfaces surrounded by lavas that poured from Belknap Crater and Little Belknap to the north and near the center of the vast flood; lavas south of the highway flowed chiefly from Cinder Cone. The first travel route across the Cascade Range here was an ancient Indian trail along the southern edge of the lava field north of the North Sister. Its first recorded use by white men came in 1862, when Felix Scott, Jr., a sub-Indian Agent, led a party eastward over it with cattle and supplies for Idaho mining regions. The route now closely followed by the present highway was discovered in 1866, and construction then began on a toll road opened for travel in 1872; it became a free county road in 1898 and a state highway in 1917. The present Scott Trail follows the old wagon route, and sections of the old toll road remain visible along the McKenzie Highway. Dee Wright, for whom the observatory was named, was a longtime forest officer, guide, and packer known throughout the Cascade mountain country who supervised the start of development work on this project but died before its completion.