Idaho State Highway 33

Idaho State Highway 33 is a state highway traversing eastern and southeastern Idaho, connecting rural communities, agricultural corridors, and recreational gateways. The route links U.S. Route 20 and the Interstate 15 corridor with the Yellowstone National Park region, passing through diverse landscapes that include the Snake River Plain, high desert, and mountain foothills. The highway serves local traffic, freight movements, and tourism flows between towns such as Arco, Idaho, Rexburg, Idaho, and the vicinity of West Yellowstone, Montana.

Route description

The highway begins near Arco, Idaho where it intersects U.S. Route 20, providing access to the Idaho National Laboratory region and the Craters of the Moon National Monument and Preserve, then proceeds southeast through Butte County toward Ririe, Idaho and Rigby, Idaho. Along its alignment it crosses the Big Southern Butte vicinity and traverses agricultural valleys tied to the Snake River irrigation network, linking to U.S. Route 26 and Interstate 15 near Idaho Falls, Idaho. The corridor continues eastward through Jefferson County and Bonneville County into Clark County, interacting with state and local roads that serve Rexburg, Idaho, St. Anthony, Idaho, and smaller communities. Approaching the state line, the highway climbs toward the Yellowstone Plateau region, providing a direct state route connection to roads used by visitors bound for Yellowstone National Park, West Yellowstone, Montana, and trailheads for public lands managed by the U.S. Forest Service.

History

The roadway traces development patterns tied to early 20th-century transportation projects and regional settlement promoted by the Union Pacific Railroad expansions and irrigation initiatives linked to the Bureau of Reclamation projects such as the American Falls Reservoir. Designation as a numbered state highway occurred during statewide highway codifications in the 1920s and 1930s influenced by federal policies like the Federal Aid Highway Act of 1921 and subsequent state highway mapping efforts overseen by the Idaho Transportation Department. Over decades, routing adjustments reflected changing priorities from rail-dominated freight to automobile and trucking corridors serving Idaho Falls, Idaho industrial nodes and tourism to Yellowstone National Park and Grand Teton National Park visitors. Infrastructure improvements have been tied to wider regional programs, including projects supported by the Federal Highway Administration, energy-access work for the Idaho National Laboratory, and Cold War-era transportation planning influenced by military logistics considerations associated with regional training areas. Historical events impacting the route include seasonal closures and avalanche mitigation in high-elevation stretches, as experienced near passes used by early 20th-century automobile clubs and Civilian Conservation Corps road crews.

Major intersections

Major connections along the corridor include the junction with U.S. Route 20 near Arco, Idaho, intersections with Idaho State Highway 22 and Idaho State Highway 28 that serve Rexburg, Idaho and Salmon, Idaho-bound traffic, and a linkage to Interstate 15 facilitating access to Pocatello, Idaho, Boise, Idaho, and Salt Lake City, Utah. The route also intersects regional arterials and county roads providing access to Idaho Falls Regional Airport, industrial parks, and agricultural distribution centers tied to Idaho State University markets and Brigham Young University–Idaho enrollment travel. Near its eastern terminus, connections enable transitions to Montana Highway routes toward West Yellowstone, Montana and Bozeman, Montana, linking with national networks used by National Park Service traffic and state tourism initiatives.

Traffic and maintenance

Traffic composition includes a mix of local commuter traffic from towns such as Rexburg, Idaho and Rigby, Idaho, seasonal tourist volumes bound for Yellowstone National Park, and freight movements supporting agricultural shipments and energy-sector logistics for facilities like the Idaho National Laboratory. Maintenance responsibilities rest with the Idaho Transportation Department, which coordinates snow removal, pavement preservation, and safety upgrades with federal partners including the Federal Highway Administration and regional entities such as county public works departments in Butte County, Jefferson County, and Clark County. Traffic studies have referenced operational interactions with U.S. Route 20, Interstate 15, and state truck routes managed under federal hours-of-service regulations influencing freight flows between Boise, Idaho and Yellowstone National Park corridors.

Future developments and projects

Planned and proposed improvements have been part of statewide transportation planning overseen by the Idaho Transportation Department and regional Metropolitan Planning Organizations influenced by Federal Highway Administration funding cycles and federal infrastructure bills. Projects under consideration include pavement rehabilitation, intersection realignments to improve safety near growing population centers like Rexburg, Idaho and Idaho Falls, Idaho, and enhanced signage and pullouts to serve increased visitation to Yellowstone National Park and Craters of the Moon National Monument and Preserve. Coordination with federal land managers such as the National Park Service and the U.S. Forest Service aims to mitigate seasonal congestion, improve wildlife crossings, and implement avalanche-control measures where applicable. Future corridors and multimodal planning reference connections to Interstate 15, U.S. Route 20, and interstate commerce routes that tie into freight distribution hubs in Pocatello, Idaho and Boise, Idaho.

Category:State highways in Idaho