Historic Resource Study, Crater Lake National Park, Oregon, 1984
VIII. Roads of Crater Lake National Park
B. Entrance Road and Bridges
13. Evaluations and Recommendations
Because of their initial construction as temporary structures, the first bridges in Crater Lake National Park were ultimately replaced as soon as funds were available. Originally built for horse-drawn vehicles, the structures soon proved inadequate for heavier traffic. None of the bridges within the park are recommended as being historically significant.
The rim road built around the caldera from 1915 to 1919 was without doubt the single greatest achievement in the development of a road system within Crater Lake National Park. Extremely difficult problems were encountered due to the rough terrain and short working season–problems peculiar to this particular road-building activity. Although the new road begun in 1931 followed the old route whenever possible, the unfavorable features of the old road were entirely eliminated. At the same time, portions of the old road were obliterated by the planting of shrubs and the application of sod, so that in many places it became impossible to detect the course of the older route. Portions of the old rim road are now being used as trails. Due to a lack of integrity, the rim road is not considered eligible for nomination to the National Register of Historic Places.