Boise to Yellowstone Road Trip: The Easy 5-Hour US-20 Drive (2026)
Boise to Yellowstone is the easiest major-city drive to America's first national park — 280 miles of mostly flat US-20 across southern Idaho, no mountain passes, no overnight stop required. Five hours after leaving Boise you're in Island Park, Idaho, just 30 minutes from Yellowstone's West Entrance. This guide covers the route, the best stops at Shoshone Falls and Craters of the Moon, the weekend trip plan, and why Island Park is the closest Yellowstone basecamp for Idahoans.
Drive — Don't Fly
Boise is one of the only major Western cities where flying to Yellowstone almost never makes sense. BOI → IDA exists, but door-to-door takes roughly as long as just driving — and costs 2–3× more once you add the rental car. Drive almost every time: bring all your gear, stop where you want, arrive on your schedule. Compare to our Denver and Seattle road trips — those need 2 days each way. Boise is one shot.
The US-20 Route, Mile by Mile
I-84 east to Bliss, then US-20 east straight across southern Idaho to Island Park. About 280 miles, roughly 5 hours, no mountain passes.
- Boise → Mountain Home: 45 miles, ~55 min via I-84 E
- Mountain Home → Twin Falls: 90 miles, ~1 hr 20 min via I-84 E
- Twin Falls → Carey: 75 miles, ~1 hr 15 min via US-93 N → US-26/US-20 E at Bliss
- Carey → Craters of the Moon: 25 miles, ~30 min via US-20 E
- Craters of the Moon → Idaho Falls: 80 miles, ~1 hr 15 min via US-20 E / US-26 E
- Idaho Falls → Ashton: 50 miles, ~50 min via US-20 N (last fuel and groceries)
- Ashton → Island Park: 25 miles, ~30 min via US-20 N
Interactive route map: /from/boise.
Best Stops Along the Way
Shoshone Falls (Twin Falls)
The "Niagara of the West" — 212 feet tall, taller than Niagara. 15 minutes off I-84. Best in spring and early summer. Small per-vehicle fee. Pair with lunch at Elevation 486 overlooking the Snake River canyon.
Craters of the Moon National Monument
Otherworldly lava flows, cinder cones, and lava tubes. NASA trained Apollo astronauts here. Free with America the Beautiful Pass. A 30-minute detour off US-20 — do the 7-mile Loop Road or just hike up Inferno Cone for a 10-minute leg-stretch.
Idaho Falls
Last full-service city before Island Park. Costco, Target, Walmart, cheap gas. Stock up on cabin groceries here and skip the small markets up in Island Park.
Mesa Falls (Optional Ashton Detour)
Upper and Lower Mesa Falls — the last large undammed waterfalls in the Columbia River basin — are 30 minutes off US-20 via the Mesa Falls Scenic Byway from Ashton. Save it for a slower return drive or a day trip from the cabin. See our Mesa Falls history article.
Ashton
Last fuel and grocery before the cabin. Top off here if you didn't stock up in Idaho Falls.
The Boise Weekend Yellowstone Trip
Boise is one of the only major cities where a Yellowstone weekend is actually realistic. The standard 4-night Friday-to-Tuesday plan:
- Friday: Leave Boise after work. Arrive Island Park by dinner. Hot tub, sunset on the deck.
- Saturday: Yellowstone West Entrance — Old Faithful, Grand Prismatic, Midway Geyser Basin.
- Sunday: Lamar Valley wildlife loop OR fly fishing on the Henry's Fork.
- Monday: Mesa Falls scenic drive, Big Springs, or a Grand Teton day trip (~2 hours south).
- Tuesday: Slow morning, easy 5-hour return on US-20.
For longer trips, pair this with our 5-day itinerary or the 7-day plan.
Why Island Park is the Best Basecamp
For Boise visitors, Island Park is the closest meaningful lodging to Yellowstone — closer than West Yellowstone hotels (which run 2–3× the price in summer) and a fraction of Jackson Hole. 30 minutes from the West Entrance, about 2 hours from Grand Teton — one basecamp covers both parks.
Lodgepole Pines Retreat sleeps 12, has a full kitchen, hot tub, washer/dryer, and a quiet forest setting. Idaho prices, not Wyoming prices.
See Island Park vs. border towns and where to stay near Yellowstone for full lodging comparisons.
Road Trip Tips & Logistics
No Mountain Passes
The US-20 route doesn't cross any major passes — the gentle climb from Ashton onto the Henrys Fork plateau is the highest point. Winter still slows things, but no chains-required passes like the Seattle or Denver drives.
Time Zones
Boise and Island Park are both Mountain Time. No time change — a nice perk.
Gas & EV Charging
Easy fuel along I-84 and US-20. Reliable EV fast-charging in Mountain Home, Twin Falls, Idaho Falls, and Rexburg. Island Park has limited charging; top off in Idaho Falls or Rexburg. Yellowstone only has one in-park gas station (Old Faithful) — fuel in Ashton or Island Park first.
Cell Service
Solid along the route with dead zones around Craters of the Moon. Spotty inside Yellowstone. Download offline maps and podcasts before leaving.
Best Season
Mid-June through September is ideal. May and October work — check Yellowstone road openings. Winter (Nov–Apr) is fully drivable on the Boise route but West Entrance is closed to wheeled vehicles in winter — snowmobile and snowcoach only.
Frequently Asked Questions
How long is the drive from Boise to Yellowstone?
About 280 miles and 5 hours via I-84 East and US-20 East to Island Park (30 minutes from the West Entrance). No overnight needed.
Should I fly or drive?
Drive. Boise is one of the rare cities where flying almost never wins on time or cost. See our airport guide for the full comparison.
Can I do this as a weekend trip?
Yes — Friday after work to Island Park, two park days, drive home Sunday or Monday.
Where should I stay near Yellowstone?
Island Park, Idaho — 30 minutes from the West Entrance. Compare all gateway towns or see our 3-day Yellowstone itinerary.
Related Guides
- From Boise: Origin Page with Interactive Map
- Salt Lake City to Yellowstone Road Trip
- Denver to Yellowstone Road Trip
- Seattle to Yellowstone Road Trip (I-90)
- Driving Island Park to Yellowstone
- 3-Day Yellowstone Itinerary
- Yellowstone Packing List
- Mesa Falls History (Ashton detour)