
Isa Lake Bridge - Grand Loop Road - Wyoming
Posted by:
Volcanoguy
N 44° 26.478 W 110° 43.150
12T E 522347 N 4920927
The Isa Lake Bridge in the Grand Loop Road Historic District at Yellowstone National Park.
Waymark Code: WMDPF5
Location: Wyoming, United States
Date Posted: 02/10/2012
Views: 21
The first road from Old Faithful to West Thumb was completed in 1892 and passed Isa Lake. In the 1930’s planning began for improvement of the route and the plan included a crossing of Isa Lake. Originally a culvert was initially going to be used for the crossing but the crossing design evolved into a low timber bridge “to preserve the natural existing conditions as near as possible.”
Construct began on the route in 1941 and the bridge was completed in July 1942 but the complete route was not completed until after World War II. The eight-span bridge has a total length of 160 feet. The bridge deck has a width of 28 feet with guardrails of 14-inch diameter logs.
The Grand Loop Road Historic District is a 140.14 mile road system which provides the primary visitor access to the major points of interest and visitor facilities in Yellowstone National Park. The Grand Loop Road extends south from the origin point in Mammoth to Norris Junction (Segment A); travels in a westerly direction to Madison Junction (Segment B); extends south to Old Faithful (Segment C); the turns east to West Thumb (Segment D); roughly follows the lakeshore north to Fishing Bridge (Segment E); then northwesterly to Canyon Junction (Segment F); northeast from Canyon to Tower (Segment G); then turns west towards Mammoth (Segment H) returning to the origin point; a center section connects Norris Junction and Canyon Junction (Section I).
The current alignment of the Grand Loop Road grew from early wagon trails that followed river valleys and lakeshores. During the first 30 years of development, the road was in constant change, but by 1905 the interior road system connecting natural attractions, hotels, and entrance roads had stabilized into the present figure-eight configuration known as the Grand Loop Road. Having been built over many decades with many different standards, techniques, materials, and under many administrators, the Grand Loop Road retains basically the same configuration as it was first built, although some small sections have been abandoned or transformed into scenic roads.
Above information comes from the Historic District Registration Form on the NPS website: (
visit link)