Historic Resource Study, Crater Lake National Park, Oregon, 1984
VIII. Roads of Crater Lake National Park
B. Entrance Road and Bridges
7. Plans Made for First Rim Road
In 1913 work began on the road that six years later would encircle the lake but that would be only partially satisfactory because of the necessity of dodging around boulders and trees while following a track that was boggy and usable only a few weeks out of each year. Some of the $125,000 appropriated for road work that season was utilized to purchase heavy machinery for the upcoming rim road work.
By October 1914 more than twenty miles of government roads had been finished that year alone, bringing the total number of miles completed within the park to forty:
park line on Fort Klamath side to rim of lake via Anna [Annie] Creek Canyon, fourteen miles;
Kirk side from park line to Kerr Notch via Sand Creek, nine miles;
Kerr Notch to foot of Cloudcap, three miles;
Anna Creek to Sand Creek, twelve miles;
elimination of “Corkscrew” of Medford Road, 1-1/2 miles;
plus, the location was made this year and the clearing begun for a road from the Crater Lake Lodge to The Watchman, about four miles. 
In July 1915 Stephen T. Mather, newly appointed assistant to the secretary of the interior, conducted the first of his official mountain trips–expeditions that he personally financed to give influential persons firsthand park experience and the opportunity to see for themselves the problems facing national parks. In August he inspected facilities at Crater Lake and Mount Rainier, finding at the former crude roads and poor concessions. By the end of 1915 the portion of the rim road between Kerr Notch and the lodge had been built and the subgrade of all three entrance roads completed and made ready for hard surfacing . A summary of road progress in the park by 1916 gave the following approximate figures on work accomplished to date: 44 miles of road had been graded, including 7 miles from the park headquarters to the Medford entrance, 8 miles from park headquarters to the Klamath entrance, 5 miles from park headquarters to the rim, 8 miles from the Corps of Engineers’ camp to the Pinnacles road, 6-1/2 miles from the Pinnacles entrance to Kerr Notch, 3 miles from Kerr Notch to Cloudcap where the grading ended, 1-1/2 miles from the Corps of Engineers camp to the rim, and then 5 miles from Crater Lake Lodge to the end of grading Ungraded stretches consisted of 12 miles of rim road and 1-1/2 miles of the Sun Notch road. A total of 57-1/2 miles of roadway now existed within the park. 
In 1918 Congress appropriated $50,000 for completion of grading of the rim road, but due to increased labor costs, difficulties in acquiring workers, and other problems, it was unlikely that necessary work on improving the fourteen miles between Cloudcap and The Watchman could be accomplished unless an additional $7,000 could be obtained. Although the Corps of Engineers still had charge of road work, Congress was expected to authorize transfer of this responsibility to the National Park Service. This action would be based on the belief that the superintendent could oversee the work necessary to complete the rim road at less expense than would be entailed in organizing another Corps of Engineers field party.  A rude rim road finally encircled the lake by 1919, quickly becoming a popular drive for tourists rambling around southern Oregon. In this same year the U.S. Army Corps of Engineers left Crater Lake, the last national park in which they were involved. In 1922 the Diamond Lake entrance road was built, replacing the Diamond Lake Trail.