How far is American Falls, ID from Post Falls, ID?
The driving distance from American Falls, ID to Post Falls, ID is about 556 miles (894.8 km), with a travel time of about 08h 29m by car.
- The straight-line flight distance is about 394.6 miles (635.1 km).
- For a round trip, plan for roughly 16h 59m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 6:00 AM to 7:30 AM MDT.
Reverse, save, or send this route
This drive is better planned with a longer stop or an overnight stay. Copy the route link, send it to another device, or print a clean version before you head out.
This drive is better planned with a longer stop or an overnight stay.
Flight Distance
Driving Distance
Gas Cost Calculator
Leave and Arrive Planner
Pick a departure time to see your estimated arrival and same-day return window.
Drive time stays fixed at 08h 29m.
Starting early still helps, but most travelers will want a longer stop or an overnight stay on a route this long.
You are leaving earlier than the recommended window, which gives you extra margin for breaks and traffic.
Halfway Point
A useful midpoint for breaks, coffee, or meeting in the middle.
City in Lemhi County, Idaho, United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Light Rain then Showers And Thunderstorms
Rain
Driving Route Map
The map below follows the saved road route between American Falls and Post Falls.
Turn-by-Turn Driving Directions
Step-by-step road directions between American Falls and Post Falls.
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1
Start on the route
53 m · 15 sec
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2
Turn right onto Fort Hall Avenue
53 m · 13 sec · Fort Hall Avenue
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3
Turn left onto Harrison Street
1352 ft · 27 sec · Harrison Street
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4
Continue on Pocatello Avenue
1.3 km · 1 min · Pocatello Avenue
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5
At the end of the road, turn right onto Pocatello Avenue
2778 ft · 51 sec · Pocatello Avenue
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6
Take the ramp left
1408 ft · 34 sec
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7
Merge slight left
21.8 mi · 21 min
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8
Keep slight left to continue on Idaho Falls
3046 ft · 40 sec
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9
Merge slight right
244.5 mi · 3 hr 50 min
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10
Take the exit slight left toward I 90 West: Missoula
2808 ft · 1 min
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11
Merge slight left onto I 90 West: Missoula
285.8 mi · 4 hr 50 min
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12
Take the exit slight right toward Spokane Street
1913 ft · 50 sec
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13
Turn right onto North Spokane Street
1710 ft · 1 min · North Spokane Street
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14
Turn left onto West 10th Avenue
872 ft · 38 sec · West 10th Avenue
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15
Arrive at your destination
0 m · 1 sec · West 10th Avenue
Car Route Details
A richer read on the saved driving route between American Falls and Post Falls.
Long-distance drive
This route is long enough that fuel, rest stops, weather, and timing matter more than any single maneuver.
I 90 West
Merge slight left onto I 90 West: Missoula
286 mi · 04h 50m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
Better with a longer stop
This route is long enough that most travelers will be better off planning an overnight stay or a more deliberate stop window.
Light Rain then Showers And Thunderstorms leaving American Falls and Rain near Post Falls.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from American Falls to Post Falls?
The road trip is about 556 miles (894.8 km) and usually takes 08h 29m in normal driving conditions.
Is this a same-day trip or an overnight route?
This route is long enough that most travelers will be better off planning an overnight stay or a more deliberate stop window.
What is the halfway point on this route?
Salmon is a useful midpoint, sitting about 277.7 miles from American Falls and 278.3 miles from Post Falls.
How much longer is the road route than the straight-line distance?
The direct path is about 394.6 miles (635.1 km), while the road route adds roughly 161.4 extra miles because roads do not follow the straight air line.
When is the best time to leave for this route?
A good departure window is usually 6:00 AM to 7:30 AM MDT. Starting early still helps, but most travelers will want a longer stop or an overnight stay on a route this long.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $76.38 one way or $152.76 round trip. Estimated CO2 is about 174.4 kg one way.
Do you cross a time zone on this route?
Yes. There is about a 1 hour time difference between American Falls and Post Falls, so arrival and return times should be read in local time.
What should you check before leaving?
Before you leave, expect Light Rain then Showers And Thunderstorms around American Falls and Rain near Post Falls.
Flight Path Map
This map shows the direct air route between American Falls and Post Falls. Straight-line distance: 394.63 mi (635.09 km).
#1 American Falls
City in Idaho
| Population | 4,315 |
| Coordinates | 42.7860200, -112.8544400 |
| Altitude | 1343 |
| Country | United States |
#2 Post Falls
City in Kootenai County, Idaho, United States
| Population | 36,250 |
| Coordinates | 47.7179600, -116.9515900 |
| Altitude | 665 |
| Country | United States |
End: West 10th Avenue (-116.951612, 47.717931)
Estimated Travel Time
Distance: 895 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 18h 31m |
| 40 mph (64.37 km/h) | 13h 54m |
| 50 mph (80.47 km/h) | 11h 07m |
| 60 mph (96.56 km/h) | 09h 16m |
| 70 mph (112.65 km/h) | 07h 56m |
| 80 mph (129 km/h) | 06h 56m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.89 | $76.38 | $152.76 |
| Mid-grade | $4.23 | $83.01 | $166.02 |
| Premium | $4.55 | $89.25 | $178.50 |
| Diesel | $5.41 | $106.18 | $212.37 |
Assumes 8.3 L/100 km (about 28.3 MPG). CO2 is an estimate and varies by vehicle, fuel blend, traffic, and terrain.
Prices in Idaho · Apr 23, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.