Glenns Ferry to Post Falls is 511.1 miles and takes about 9 hours 14 minutes via I 84 and US 395, with a fuel budget near $90 and enough daylight to finish in a day. This is a long-haul drive that keeps you within the Mountain West region for its entirety. While it's possible to complete in a single day, the recommended two-day pace allows for a more relaxed experience. Consider this route if you're looking for a straightforward drive across Idaho with minimal deviations.
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
255.5 miles from Glenns Ferry, ID
A natural place for your longest stop of the day
, about 4h 27m into the drive
.
Main Roads
Road
Distance
Duration
I 84
220.2 mi
3h 54m
US 395
131.7 mi
2h 23m
Vietnam Veterans Memorial Highway
88 mi
1h 27m
I 90
25.9 mi
30m
McNary Highway
20.4 mi
21m
Umatilla-Stanfield Highway
8.2 mi
9m
Lewis and Clark Trail
4.9 mi
6m
Lewis and Clark Trail Highway
3.3 mi
4m
Longest stretch:
I 84
— 220.2 mi, about 3h 54m
Traffic on I-84
Hour-of-day weekday pattern from 185 FHWA count stations on your route.
Peak
4 PM
~2,286 veh/hr typical
· worst 2,638
Quietest
2 AM
~148 veh/hr
Peak-to-quiet ratio
15.4×
busier at peak than in the quiet hours
12a6anoon6p11p
Averaged across 52 weeks of 2023 FHWA Travel Monitoring Analysis System data. Weekday hours only (Mon–Fri).
Turn-by-Turn Driving Directions
Step-by-step road directions between Glenns Ferry, ID and Post Falls, ID.
1
Start on this road
42 ft·4 sec·this road
2
Turn right onto North Commercial Street
162 ft·9 sec·North Commercial Street
3
Turn right onto I 84 Business
0.4 mi·45 sec·West 1st Avenue
4
Turn right onto I 84 Business
0.6 mi·1 min·North Bannock Avenue
5
Take the ramp onto I 84 Business
0.2 mi·30 sec·I 84 Business
6
Merge onto I 84; US 26; US 30
88 mi·1 hr 27 min·Vietnam Veterans Memorial Highway
Use the straight / slight right lanes.
7
Continue on I 84; US 30
220 mi·3 hr 54 min·I 84; US 30
Use the straight / slight right lanes.
8
Take the exit onto US 395
0.3 mi·41 sec·US 395
Toward US 395 North: Stanfield, Hermiston
9
Continue on US 395
1.2 mi·1 min·Umatilla-Stanfield Highway
10
Continue on US 395
2.0 mi·2 min·South Main Street
11
Continue on US 395
3.2 mi·3 min·Umatilla-Stanfield Highway
12
Turn right onto Southeast 4th Street
1.6 mi·3 min·Southeast 4th Street
13
Turn left onto East Theater Lane
0.3 mi·41 sec·East Theater Lane
14
Turn right onto US 395
0.5 mi·38 sec·North 1st Street
15
Continue on US 395
3.8 mi·4 min·Umatilla-Stanfield Highway
16
Turn left onto US 395; US 730
0.7 mi·48 sec·Columbia River Highway
Use the straight / left lanes.
17
Take the exit onto US 395
0.2 mi·27 sec·US 395
Toward I 82 West, US 395 North: Kennewick, Yakima
18
Merge onto I 82; US 395
20 mi·21 min·McNary Highway
19
Keep slight right at fork onto US 395
3.3 mi·4 min·Lewis and Clark Trail Highway
Toward US 395 north to I‑182: Kennewick, Pasco, Spokane
20
Continue on US 395
1.1 mi·2 min·South US 395
21
Continue on US 395
4.9 mi·6 min·Lewis and Clark Trail
Use the straight / slight right lanes.
22
Take the exit onto US 395
0.2 mi·21 sec·US 395
Toward US 395 north, SR 397 south (Oregon Street): Spokane, FinleyUse the straight / slight right lanes.
23
Keep slight left at fork onto US 395
0.3 mi·34 sec·US 395
Toward US 395
24
Keep slight right at fork onto US 395
131 mi·2 hr 20 min·US 395
Toward US 395 North: SpokaneUse the slight right lane.
25
Merge onto I 90; US 2; US 395
26 mi·30 min·I 90; US 2; US 395
26
Take the exit onto I 90 Business
0.4 mi·48 sec·I 90 Business
Toward I 90 Business
27
Turn left onto I 90 Bus
0.4 mi·1 min·North Spokane Street
28
Turn left onto West 10th Avenue
0.2 mi·38 sec·West 10th Avenue
29
Arrive at destination
West 10th Avenue
Trip Plan
Given the 9-hour drive time, splitting this trip over two days is highly recommended for comfort. Aim to depart early in the morning to maximize daylight hours. Plan for at least two stops to break up the drive. The longest stretch without many services is on I 84, so ensure you have adequate fuel before entering that segment. Keep an eye on your fuel gauge, especially as you transition from the interstate system to other highways, as services can become less frequent.
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 255.5 miles from Glenns Ferry, ID, or about 4h 27m into the drive.
The longest continuous stretch on this route runs about 220.2 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 112 miles or 1h 54m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 255.5 miles or 4h 27m 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 255.5 miles or 4h 27m
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 5m
Traffic, exits, and arrival timing usually matter more near Post Falls, ID than in the middle of the route.
Before You Leave
+
Open the route before leaving Glenns Ferry, 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 Glenns Ferry, ID
Aim for roughly 256 miles and 4.6 hours of wheel time on this day.
Day 2
Finish the approach into Post Falls, ID
Aim for roughly 256 miles and 4.6 hours of wheel time on this day.
Your first comfortable stop window is around 112 miles from Glenns Ferry, 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 I 84 for about 220.2 miles.
Where to Stop
Rest stops, refuel points, and overnight suggestions along this route.
Place data sourced from public business listings. Hours and availability may vary.
Heads-up: tricky spots
5 of 19
5 decision points cluster between mile 323.2 and 353.5 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
6
323.2 mi into trip|~5h 42m in|US 395
Take the exit onto US 395 toward I 82 West, US 395 North: Kennewick, Yakima
Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one
Toward I 82 West, US 395 North: Kennewick, Yaki...
6
343.8 mi into trip|~6h 5m in|US 395 / Lewis and Clark Trail Highway
Keep slight right at fork onto US 395 / Lewis and Clark Trail Highway toward US 395 north to I‑182: Kennewick, Pasco, Spokane
Highway fork - watch signs carefully. Multiple destination signs - pick the right one
Toward US 395 north to I‑182: Kennewick, Pasco,...
7
353.1 mi into trip|~6h 18m in|US 395
Take the exit onto US 395 toward US 395 north, SR 397 south (Oregon Street): Spokane, Finley
Exit ramp - move to the correct lane early. Lane positioning matters here. Multiple destination signs - pick the right one
Use the straight / slight right lanes.
Toward US 395 north, SR 397 south (Oregon Stree...
6
353.2 mi into trip|~6h 19m in|US 395
Keep slight left at fork onto US 395 toward US 395
Highway fork - watch signs carefully
Toward US 395
7
353.5 mi into trip|~6h 19m in|US 395
Keep slight right at fork onto US 395 toward US 395 North: Spokane
Highway fork - watch signs carefully. Lane positioning matters here
Use the slight right lane.
Toward US 395 North: Spokane
Fuel & Cost
Regular Gas
$79.66 one way
$159.33 round trip
$3.96/gal25.4 MPG avg179 kg CO2
Fuel Type
$/gal
One Way
Round Trip
midgrade
$4.17
$83.97
$167.94
premium
$4.47
$90.03
$180.05
diesel
$4.80
$96.51
$193.01
No toll roads detected on this route.
Estimated Trip Cost (one way, 1 person)
Fuel
$80
Hotel (1n)
$80–$140
Meals
$50–$100
Total
$210–$320
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 178.8 kg one way.
Prices: EIA weekly data, 2026-07-13.
Driving Electric?
About $54 in charging
· 1 stop
· 66% less CO2
Vehicle Type
kWh
Stops
DC Fast
Home Charge
Average EV
153.3
1
$53.67
$24.53
Efficient EV
127.8
1
$44.72
$20.44
EV Truck/SUV
204.4
2
$71.55
$32.71
Gas CO2
179 kg
EV CO2
60 kg (66% 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 Jul 16, 2026
Origin
Glenns Ferry, ID
Evening
in Glenns Ferry on Saturday
Local time
7:26 PM
MDT
Current temp
104°F
Slight Chance Showers And Thunderstorms
E 6 mph20% chanceLive forecast
Special Weather Statement
Special Weather Statement issued July 16 at 3:42PM MDT by NWS Boise ID
Flash Flood Warning
Flash Flood Warning issued July 16 at 2:23PM MDT until July 16 at 5:30PM MDT by NWS Pocatello ID
Destination
Post Falls, ID
Evening
in Post Falls on Saturday
Local time
6:26 PM
PDT
Current temp
100°F
Slight Chance Showers And Thunderstorms
E 3 mph29% chanceLive forecast
Special Weather Statement
Special Weather Statement issued July 16 at 3:42PM MDT by NWS Boise ID
Flash Flood Warning
Flash Flood Warning issued July 16 at 2:23PM MDT until July 16 at 5:30PM MDT by NWS Pocatello ID
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 earlier
The destination clock does not match departure time, so double-check hotel check-in windows and late arrival plans.
Temperature spread
4 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 14m 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.
National Parks Near This Route
Worth a detour if your schedule allows.
Hagerman Fossil Beds National Monument
National Monument
During the Pliocene, this place looked quite different. Lush wetlands, forests, and grasslands provided excellent habitat for a variety of animals. From fascinating, now-extinct creatures like the sab...
21 mi from route
~53 min detour
Free
Caution: Use Caution with "Fossil Beds Information" Signs
Caution: If You Can't Reach Us By Phone, Please Email Us
Park data from the National Park Service API. Alerts update every 2 hours.
More Details
What kind of drive is this?
You'll spend 74% of your time on major highways, covering a significant distance before encountering more varied roadways. The longest uninterrupted stretch is 220.2 miles on I 84. After US 395, you'll transition to Vietnam Veterans Memorial Highway, which will feel more like surface road cruising. Expect a mix of open highway and potentially more frequent exits as you approach your destination.
74% highway — fuel and pacing are the main things to plan.
29 navigation steps total — most of the decisions cluster near the start and finish.
Longest single stretch: 220.2 mi on I 84.
How Hard Is This Drive?
9/10
This is a straightforward highway drive that stays mostly on I 84 and US 395. This route has several spots where lane changes, forks, or exits need your full attention. The trickiest moment comes around 323.2 miles in near US 395.
Driving Effort9/10
High effort - long or complex enough to need steady focus all day
Balances navigation complexity with total wheel time.
This is a demanding drive. With 19 significant decision points across 511.1 miles, you will need to stay alert - especially through interchange areas and urban stretches. Consider splitting it into segments if you are not comfortable with fast highway navigation.
Where does it get tricky?
The main spots that need attention: at 323.2 miles (US 395): Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one; at 343.8 miles (US 395 / Lewis and Clark Trail Highway): Highway fork - watch signs carefully. Multiple destination signs - pick the right one; at 353.1 miles (US 395): Exit ramp - move to the correct lane early. Lane positioning matters here. Multiple destination signs - pick the right one.
Elevation Profile
Hilly terrain with moderate elevation changes
4,002 ft618 ft
Total Climb
4,728 ft
Total Descent
5,116 ft
Highest Point
4,002 ft
~255.5 mi in
Elevation Range
3,384 ft
Notable High Points
4,002 ft at ~255.5 miles+629 ft prominence
Towns Mentioned on Route Signs
Based on OSRM destination-sign hints, not a full list of every settlement the road passes.
Between Glenns Ferry, ID and Post Falls, ID, road signs point toward Hermiston, Yakima, Pasco, Spokane and Finley.
The longest stretch is about 220.2 miles on I 84. The full list of main roads is in the Roads section above.
Yes — a 2-day pace is more comfortable than one long haul. A sensible stopping point is after roughly 256 miles on day one.
Yes — we found about 42 rest areas or service plazas within a short detour of the route (from OpenStreetMap). See the Rest Stops tab under Nearby Places for locations and mile markers. Plan to stretch, use the bathroom, and top off fluids every 2–3 hours on longer drives.
It helps. This route has a higher-than-average number of complex decision points, which get harder in the dark. If the last hour of the trip is on surface roads or mountain grades, aim to arrive at Post Falls, ID before sunset when you can. Check the Trip Plan for departure windows that land you in daylight.
Only with planning. This is a long drive for kids — consider splitting it into two days rather than pushing through. Plan at least 2 meaningful breaks. There are 42 rest areas along the route for bathroom stops.
Mostly yes along the main roads, but rural stretches through ID can have sparse or no coverage. Before you leave, download offline Google Maps or Apple Maps for the route, and consider downloading music or podcasts instead of streaming. If you depend on data for navigation, keep a paper backup of the turn-by-turn directions.
The main spots that need attention: at 323.2 miles (US 395): Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one; at 343.8 miles (US 395 / Lewis and Clark Trail Highway): Highway fork - watch signs carefully. Multiple destination signs - pick the right one; at 353.1 miles (US 395): Exit ramp - move to the correct lane early. Lane positioning matters here. Multiple destination signs - pick the right one.
Yes — Hagerman Fossil Beds National Monument. See the National Parks section for detour distances and tips on detours.
Not recommended in a single day. At 9.2 hours each way, a round trip means 18.5 hours of driving — that is an unsafe level of fatigue for most drivers. Plan at least one night at Post Falls, ID before the return drive.
