Lewiston, ID to Idaho Falls, ID is 531.1 miles and takes about 9h 52m via US 12 and I 15, with a fuel budget near $84 and enough daylight to finish in a day, though it's best as an overnight trip. This journey stays within the Mountain West region, offering a long-distance drive that requires some planning. Given the 9h 52m estimated drive time, breaking this trip into two days is a sensible approach to avoid fatigue and make the most of your travel. Consider this route if you're looking for a straightforward way to cover a significant distance within Idaho.
Trip Pace
Best split across 2 days
Treat the return leg as its own travel day rather than an afterthought.
Break Rhythm
2 planned breaks
Plan on a short reset every 3 to 4 hours to stay fresh behind the wheel.
Midpoint
265.6 miles from Lewiston, ID
A natural place for your longest stop of the day
, about 5h 37m into the drive
.
Who Is This Route For?
Family Friendly
Moderate complexity with 2 natural rest stops along the way.
Solo Traveler
9h 52m drive, plan rest stops for pacing.
Drive Character
This drive is predominantly highway, with 77% of the route utilizing major roads like US 12 and I 15. You'll encounter a significant uninterrupted stretch of 212.4 miles on US 12, which can be a good opportunity to settle in for a longer segment of driving. The route offers a mix, transitioning from the initial highway segments to the more direct interstate travel as you progress towards Idaho Falls. Expect a steady pace for much of the journey, allowing for consistent progress across the state.
Most of the miles stay on highways, which makes pacing and fuel planning easier than turn-by-turn city driving.
There are about 33 navigation steps in the underlying route data, so the final approach matters more than the middle miles.
US 12 is the longest continuous segment at about 212.4 miles.
How Hard Is This Drive?
This is a straightforward highway drive that stays mostly on US 12 and I 15. You will hit about 22 points where you need to pay attention to lane position or signs. The trickiest moment comes around 0.7 miles in near 7th Avenue.
Driving Effort6/10
Moderate - straightforward overall, but long enough or busy enough to require pacing
Balances navigation complexity with total wheel time.
This drive requires moderate attention. Across 531.1 miles you will encounter 22 spots where lane choice or exit timing matters. Not difficult for experienced highway drivers, but worth previewing the tricky sections before you go.
Where does it get tricky?
The main spots that need attention: at 0.7 miles (7th Avenue): Navigation decision point; at 0.9 miles (21st Street): Navigation decision point; at 1.9 miles (US 12): Highway fork - watch signs carefully. Lane positioning matters here. Multiple destination signs - pick the right one.
Critical Maneuvers
5 of 22 key points
These are the spots where you need to pay the most attention. Preview them before you drive.
5
0.7 mi into trip|~2m in|7th Avenue
Turn left onto 7th Avenue
Navigation decision point
5
0.9 mi into trip|~2m in|21st Street
At end of road, turn left onto 21st Street
Navigation decision point
8
1.9 mi into trip|~4m in|US 12
Keep slight right at fork onto US 12 toward US 95 South: Missoula, Boise
Highway fork - watch signs carefully. Lane positioning matters here. Multiple destination signs - pick the right one
Use the straight lane.
Toward US 95 South: Missoula, Boise
5
329.2 mi into trip|~6h 38m in
Take the exit toward I 15 South: Dillon, Idaho Falls
Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one
Toward I 15 South: Dillon, Idaho Falls
5
527.7 mi into trip|~9h 45m in|I 15 BUS; US 20
Take the exit onto I 15 BUS; US 20 toward I 15 Business, US 20 West: Historic Downtown, Arco
Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one
Toward I 15 Business, US 20 West: Historic Down...
Main Roads
Road
Distance
Duration
US 12
212.4 mi
4h 42m
I 15
198 mi
3h 5m
Jeannette Rankin Memorial Highway
111.5 mi
1h 45m
Brooks Street
3.3 mi
4m
South Boulevard
1 mi
2m
Idaho Street
0.7 mi
1m
South Utah Avenue
0.6 mi
1m
West 17th Street
0.6 mi
<1m
Longest stretch:
US 12
— 212.4 mi, about 4h 42m
Turn-by-Turn Driving Directions
Step-by-step road directions between Lewiston, ID and Idaho Falls, ID.
1
Start on this road
105 ft·9 sec·this road
2
Turn right onto Idaho Street
0.7 mi·1 min·Idaho Street
3
Turn right onto 19th Street
288 ft·18 sec·19th Street
4
Turn left onto 7th Avenue
0.1 mi·30 sec·7th Avenue
5
At end of road, turn left onto 21st Street
339 ft·10 sec·21st Street
6
Continue on US 12
1.0 mi·2 min·US 12
7
Keep slight right at fork onto US 12
7.4 mi·8 min·US 12
Toward US 95 South: Missoula, BoiseUse the straight lane.
8
Take the exit onto US 12
164 mi·3 hr 42 min·US 12
Toward US 12 East
9
Continue on US 12
33 mi·39 min·US 12
10
Continue on US 12; US 93
7.0 mi·9 min·US 12; US 93
11
Continue on Brooks Street
3.3 mi·4 min·Brooks Street
Use the straight / right lanes.
12
Continue on US 12
356 ft·16 sec·South Higgins Avenue
Use the left lane.
13
Turn right onto US 12
0.4 mi·36 sec·South 6th Street East
14
Turn left onto Arthur Avenue
0.2 mi·13 sec·Arthur Avenue
15
Continue on US 12
0.2 mi·15 sec·Madison Street
16
Take the exit onto US 12
0.2 mi·26 sec·US 12
17
Turn left onto I 90 Bus; US 12
435 ft·5 sec·Van Buren Street
18
Take the exit onto I 90 Business; US 12
0.2 mi·29 sec·I 90 Business; US 12
19
Merge onto I 90; US 12; MT 200
111 mi·1 hr 45 min·Jeannette Rankin Memorial Highway
20
Take the exit
0.5 mi·1 min
Toward I 15 South: Dillon, Idaho Falls
21
Merge onto I 15
198 mi·3 hr 5 min·I 15
22
Take the exit onto I 15 BUS; US 20
0.3 mi·46 sec·I 15 BUS; US 20
Toward I 15 Business, US 20 West: Historic Downtown, Arco
23
Continue on I 15 BUS; US 20
0.4 mi·54 sec·West Broadway Street
24
Turn right onto South Utah Avenue
0.5 mi·50 sec·South Utah Avenue
25
Enter roundabout onto South Utah Avenue
103 ft·2 sec·South Utah Avenue
26
Continue on South Utah Avenue
0.1 mi·23 sec·South Utah Avenue
27
Turn left onto Pancheri Drive
0.4 mi·42 sec·Pancheri Drive
28
Continue on West 17th Street
0.6 mi·57 sec·West 17th Street
29
Turn right onto South Boulevard
1.0 mi·2 min·South Boulevard
30
Continue on Stonebrook Lane
466 ft·14 sec·Stonebrook Lane
31
Turn right onto West Stone Run Lane
241 ft·16 sec·West Stone Run Lane
32
Turn left onto Charleston Lane
152 ft·6 sec·Charleston Lane
33
Arrive at destination
Charleston Lane
Trip Plan
Given the 9h 52m duration, this trip is best split over two days to ensure a safe and enjoyable experience. Plan to depart in the morning to maximize daylight, especially if you're breaking it up. With two recommended stops, you can find convenient places to rest and refuel along the way. Keep an eye on your fuel levels, particularly during the 212.4-mile stretch on US 12, where services might be less frequent. The $84 fuel cost is an estimate, so it's wise to budget slightly more for unexpected price fluctuations.
Morning Departure
Start early — leave by 6-7 AM to arrive at a reasonable hour.
Evening Departure
This is a long drive — plan for a morning departure or consider splitting it into two days.
This drive is better paced as a 2-day trip.
Plan roughly 2 meaningful breaks for fuel, food, and rest.
The halfway point lands around 265.6 miles from Lewiston, ID, or about 5h 37m into the drive.
The longest continuous stretch on this route runs about 212.4 miles.
Consider an overnight stop or starting very early.
Departure
Before you leave
Start with fuel, water, and navigation already sorted so the first hour feels easy.
First stop
Around 117 miles or 2h 40m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 265.6 miles or 5h 37m in
This is the best place for your longest stop, a real meal, and a full fuel check.
Overnight split
Day 1 wrap after about 265.6 miles or 5h 37m
Stop before fatigue turns the last few hours into a grind. You want day two to start fresh, not just resumed.
Final approach
Final hour starts around 8h 52m
Traffic, exits, and arrival timing usually matter more near Idaho Falls, ID than in the middle of the route.
Before You Leave
+
Open the route before leaving Lewiston, ID so your first major turns are already loaded.
+
Leave with enough water and a charging cable within reach, not packed away.
+
Check your fuel range against the first long segment, especially if you are starting outside city service areas.
+
Pick one backup stop option before the midpoint in case traffic changes your pacing.
+
Treat this as a 2-day road trip and book the overnight stop before the busiest arrival window.
Day 1
Settle into the route from Lewiston, ID
Aim for roughly 266 miles and 4.9 hours of wheel time on this day.
Day 2
Finish the approach into Idaho Falls, ID
Aim for roughly 266 miles and 4.9 hours of wheel time on this day.
Your first comfortable stop window is around 117 miles from Lewiston, ID.
This route usually feels better as a 2-day drive than as one long push.
Plan about 2 real breaks rather than only quick fuel stops.
The longest stretch is on US 12 for about 212.4 miles.
Where to Stop
Rest stops, refuel points, and overnight suggestions along this route.
Halfway Point
Midpoint
About 265.6 mi from Lewiston, ID
· 5h 37m into the drive
Place data sourced from public business listings. Hours and availability may vary.
Fuel & Cost
Regular Gas
$84.16 one way
$168.32 round trip
$4.03/gal25.4 MPG avg186 kg CO2
Fuel Type
$/gal
One Way
Round Trip
midgrade
$4.22
$88.22
$176.43
premium
$4.53
$94.74
$189.48
diesel
$5.61
$117.26
$234.52
No toll roads detected on this route.
Estimated Trip Cost (one way, 1 person)
Fuel
$84
Hotel (1n)
$80–$140
Meals
$50–$100
Total
$214–$324
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 185.8 kg one way.
Prices: EIA weekly data, 2026-04-13.
Driving Electric?
About $56 in charging
· 1 stop
· 67% less CO2
Vehicle Type
kWh
Stops
DC Fast
Home Charge
Average EV
159.3
1
$55.77
$25.49
Efficient EV
132.8
1
$46.47
$21.24
EV Truck/SUV
212.4
2
$74.35
$33.99
Gas CO2
186 kg
EV CO2
62 kg (67% less)
Plan for 1 charging stop. A 30-minute DC fast charge mid-route should be enough to complete the trip comfortably.
DC fast charging avg $0.35/kWh. Home charging avg $0.16/kWh. US grid CO2: 0.39 kg/kWh.
Travel Intel
Current conditions at both ends of the drive.
Forecast as of Apr 15, 2026
Origin
Lewiston, ID
Afternoon
in Lewiston on Friday
Local time
2:46 PM
PDT
Current temp
64°F
Unavailable
Live forecast
Destination
Idaho Falls, ID
Afternoon
in Idaho Falls on Friday
Local time
3:46 PM
MDT
Current temp
63°F
Unavailable
Live forecast
Seasonal Notes
Summer travel usually means heavier construction, hotter rest stops, and busier weekend traffic around major cities.
Winter travel shortens daylight, so a route that looks manageable on paper can feel much longer after dark.
Holiday weekends tend to make both departure and arrival windows slower than the raw route time suggests.
For long drives, weather on day two can matter just as much as conditions at departure, so check the whole travel window rather than only the first day.
Time zone
1 hour later
The destination clock does not match departure time, so double-check hotel check-in windows and late arrival plans.
Temperature spread
1 degrees cooler at arrival
A meaningful temperature swing is a good cue to rethink layers, water, and how soon you want to arrive.
Road read
9h 52m on the road
This is long enough that the arrival forecast matters almost as much as departure conditions. Recheck both ends before you roll.
Weather data from the National Weather Service. Conditions may change; check closer to your travel date.
Frequently Asked Questions
The drive from Lewiston, ID to Idaho Falls, ID covers 531.1 miles and takes about 9h 52m without stops. Add 15-30 minutes for a fuel or rest stop on longer drives.
The main roads are US 12, I 15, Jeannette Rankin Memorial Highway. Expect a mix of highway and local road driving.
Consider an overnight stop or starting very early.
Yes. This route is usually more comfortable as a 2-day drive. A sensible stopping point is after roughly 266 miles on day one.
The midpoint is about 265.6 miles from Lewiston, ID. Look for rest areas, gas stations, or food options near the halfway mark.
At current regular gas prices, expect to spend about $84.16 one way. This estimate uses 25.4 MPG — your actual cost will vary with your vehicle's fuel efficiency and current gas prices.
Start early — leave by 6-7 AM to arrive at a reasonable hour. This is a long drive — plan for a morning departure or consider splitting it into two days.
Plan about 2 meaningful breaks for fuel, food, or rest. Plan on a short reset every 3 to 4 hours to stay fresh behind the wheel.
This drive requires moderate attention. Across 531.1 miles you will encounter 22 spots where lane choice or exit timing matters. Not difficult for experienced highway drivers, but worth previewing the tricky sections before you go.
The main spots that need attention: at 0.7 miles (7th Avenue): Navigation decision point; at 0.9 miles (21st Street): Navigation decision point; at 1.9 miles (US 12): Highway fork - watch signs carefully. Lane positioning matters here. Multiple destination signs - pick the right one.
The route from Lewiston, ID to Idaho Falls, ID does not surface many named destination signs beyond the main corridor.
