State index
Idaho
Plan Route 20 across Idaho from Island Park through Rexburg, Idaho Falls, Boise, Caldwell, and Parma to the Oregon state line.
Idaho
Idaho carries Route 20 from the forests west of Yellowstone across the Snake River Plain, through the high desert, and into the Treasure Valley before the road reaches Oregon. Use this page to divide that long crossing into six manageable corridor stages, choose the right overnight anchors, and decide where a scenic stop deserves more time.
Printable companion: Use the Idaho Route 20 State Planner to divide the six corridor stages, choose an overnight base, and record range, weather, and border-handoff checks on paper.
Cross-country role
Idaho is the transition between the Yellowstone landscape and Oregon’s high desert. In the full Miami to Boston to Route 20 journey, Boise is the major city anchor, but the smaller towns determine how comfortably the state can be crossed.
For the Yellowstone re-entry, begin with Island Park and Ashton. Rexburg and Idaho Falls provide the strongest eastern Idaho services. Arco and Fairfield frame the quieter interior, while Mountain Home, Boise, Caldwell, and Parma carry the route toward the Oregon line.
Choose an Idaho planning lane
Yellowstone re-entry
West Yellowstone, Island Park, and Ashton
Choose this stage for the park-west reset, forest scenery, and the first practical Idaho gateway.
Eastern Idaho
Rexburg, Idaho Falls, and Arco
Use Rexburg or Idaho Falls for services and an overnight before turning into the high desert near Arco.
Treasure Valley
Fairfield, Mountain Home, Boise, and Caldwell
Choose this stage for a Boise-centered stop or the final Idaho drive toward the state line.
Oregon handoff
Caldwell, Parma, Nyssa, Ontario, and Vale
Use the border section to connect Idaho's services with the longer eastern Oregon crossing.
Drive Idaho in six corridor stages
Read these in east-to-west order. The first three stages have relatively frequent town anchors; the interior and border stages require more deliberate fuel, food, weather, and daylight planning.
Stage 1 · Park west
West Yellowstone, Island Park, and Ashton
Re-enter Route 20 west of Yellowstone, use Island Park for a quieter reset, and reach Ashton as a practical Idaho gateway.
Stage 2 · Upper valley
Ashton, St. Anthony, and Rexburg
Move through the upper Snake River Plain, with St. Anthony as a support stop and Rexburg as the stronger overnight base.
Stage 3 · City to desert
Rexburg, Idaho Falls, and Arco
Use Idaho Falls for city services before the landscape opens and Arco becomes the gateway to the interior.
Stage 4 · High desert
Arco, Carey, Picabo, and Fairfield
Plan a quieter drive around volcanic country, Carey Lake, Silver Creek, and widely spaced small-town services.
Stage 5 · Treasure Valley
Fairfield, Mountain Home, Boise, and Caldwell
Shift from the interior to the state's largest city anchor, then continue through Caldwell toward the border.
Stage 6 · State line
Caldwell, Parma, Nyssa, Ontario, and Vale
Cross from Idaho into Oregon through agricultural communities and prepare for the longer high-desert distances beyond Vale.
Idaho towns from east to west
The town guides below help separate overnight anchors from shorter history, nature, and service stops.
Forest reset
On Route 20
Island Park
A quieter base for forest scenery and a reset after West Yellowstone.
Gateway town
On Route 20
Ashton
A practical gateway for the upper valley and nearby waterfall country.
Support stop
On Route 20
St. Anthony
A useful services stop between Ashton and Rexburg, with regional recreation nearby.
Overnight base
On Route 20
Rexburg
A strong eastern Idaho base for an overnight and optional regional side trips.
River city
On Route 20
Idaho Falls
The eastern corridor's primary city anchor for riverfront time, museums, food, and services.
High-desert gateway
On Route 20
Arco
A history and services stop before volcanic landscapes and the quieter interior drive.
Wetlands pause
On Route 20
Carey
A proportional services stop with Carey Lake as an optional birding and fishing pause.
Nature stop
On Route 20
Picabo
The access point for a planned Silver Creek nature, birding, or fishing outing.
Interior reset
On Route 20
Fairfield
A small-town reset between the high desert and the longer approach to Mountain Home.
Transition town
On Route 20
Mountain Home
A practical transition from the quieter interior into the Treasure Valley.
Major city
On Route 20
Boise
Idaho's strongest city anchor for a full afternoon, evening, or overnight.
Valley base
On Route 20
Caldwell
A Treasure Valley stop that works as an overnight before the Oregon crossing.
Border history
On Route 20
Parma
A short history-and-parks stop before Route 20 crosses into Oregon.
Idaho trips from east to west
Short scenic drive
West Yellowstone to Island Park
Choose the shortest park-west reset when the day already includes substantial Yellowstone time.
Gateway scenic drive
West Yellowstone to Ashton
Continue through Island Park to reach a practical Idaho gateway town.
East Idaho weekend
Ashton to Rexburg
Plan a relaxed overnight around upper-valley towns and one optional outdoor extension.
City and history weekend
Rexburg to Arco
Pair Idaho Falls city time with Arco and a planned volcanic-country outing.
Interior nature weekend
Arco to Fairfield
Choose one main nature focus around volcanic country, Carey Lake, or Silver Creek.
Treasure Valley weekend
Fairfield to Caldwell
Use Boise as the primary stop while moving from the interior toward the state line.
Border weekend
Caldwell to Vale
Plan a compact Idaho–Oregon overnight around border history, Ontario services, and the Vale handoff.
Continue into Oregon
Use the Oregon route guide to plan the longer high-desert crossing from Vale through Burns and Bend, then the final westbound drive to the Pacific at Newport.