How far is Decatur, IL from Troy, MO?
The driving distance from Decatur, IL to Troy, MO is about 164.7 miles (265 km), with a travel time of about 03h 28m by car.
- The straight-line flight distance is about 123.4 miles (198.6 km).
- For a round trip, plan for roughly 06h 56m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 6:00 AM to 8:00 AM CST.
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 03h 28m.
An early departure helps you fit a real stop into the day without turning the return into a late-night drive.
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.
Human settlement in United States of America
Route Weather Snapshot
Check the forecast at both ends before you head out.
Chance Rain Showers
Chance Rain Showers then Patchy Fog
Driving Route Map
The map below follows the saved road route between Decatur and Troy.
Turn-by-Turn Driving Directions
Step-by-step road directions between Decatur and Troy.
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1
Start on East Wood Street
155 m · 23 sec · East Wood Street
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2
Turn left onto South Franklin Street
1982 ft · 49 sec · South Franklin Street
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3
Turn left onto West Eldorado Street
35.8 mi · 41 min · West Eldorado Street
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4
Take the exit slight right toward I 55 South, I 72 West: Saint Louis, Jacksonville
5.3 mi · 7 min
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5
Keep slight right to continue on I 72 West, US 36 West: Jacksonville
62.5 mi · 1 hr 7 min
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6
Take the exit slight right toward US 54, IL 107: Griggsville, Pittsfield
1298 ft · 25 sec
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7
Turn slight left
5.3 mi · 8 min
-
8
Turn right onto East Washington Street
8.9 mi · 14 min · East Washington Street
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9
Turn straight
10 mi · 14 min
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10
Turn left onto North 3rd Street
1.9 mi · 5 min · North 3rd Street
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11
Continue straight
15.1 mi · 26 min
-
12
Continue straight
898 ft · 29 sec
-
13
Take the ramp left toward US 61 South: Troy
1481 ft · 19 sec
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14
Merge slight left onto Avenue of the Saints
17.4 mi · 20 min · Avenue of the Saints
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15
Take the exit slight right toward MO 47: Troy, Winfield
990 ft · 24 sec
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16
Turn straight
921 ft · 31 sec
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17
Turn left onto North Lincoln Drive
1334 ft · 30 sec · North Lincoln Drive
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18
Turn right onto East Cherry Street
2220 ft · 44 sec · East Cherry Street
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19
Enter the roundabout and take exit 2 toward East Cherry Street
20 m · 2 sec · East Cherry Street
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20
Exit the roundabout onto East Cherry Street
1052 ft · 27 sec · East Cherry Street
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21
Turn left onto 2nd Street
30 m · 6 sec · 2nd Street
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22
Turn right
30 m · 7 sec
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23
Arrive at your destination
0 m · 1 sec
Car Route Details
A richer read on the saved driving route between Decatur and Troy.
Interchange-aware route
The drive includes several ramps, exits, or merges, so checking the next few maneuvers before busy interchanges is useful.
I 72 West
Keep slight right to continue on I 72 West, US 36 West: Jacksonville
62.5 mi · 01h 07m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A longer out-and-back drive
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
Chance Rain Showers leaving Decatur and Chance Rain Showers then Patchy Fog near Troy.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Decatur to Troy?
The road trip is about 164.7 miles (265 km) and usually takes 03h 28m in normal driving conditions.
Is this a same-day trip or an overnight route?
This is still possible in one day, but it becomes a long driving day. Leaving early and planning your stop window matters more here.
What is the halfway point on this route?
Lynnville is a useful midpoint, sitting about 82.2 miles from Decatur and 82.5 miles from Troy.
How much longer is the road route than the straight-line distance?
The direct path is about 123.4 miles (198.6 km), while the road route adds roughly 41.3 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 8:00 AM CST. If you want a more comfortable same-day return, try to leave by 10:04 AM CST.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $27.53 one way or $55.07 round trip. Estimated CO2 is about 51.6 kg one way.
What should you check before leaving?
Before you leave, expect Chance Rain Showers around Decatur and Chance Rain Showers then Patchy Fog near Troy.
Stop Ideas Near Lynnville
Useful break, food, and waypoint ideas within about 15 miles of the route midpoint.
Transit and Meeting Points
Useful pickup, handoff, or rendezvous points close to Lynnville.
Carlinville
Springfield station
Alton
Macomb
Flight Path Map
This map shows the direct air route between Decatur and Troy. Straight-line distance: 123.42 mi (198.63 km).
#1 Decatur
The most populous city in Macon County, Illinois.
| Population | 70,007 |
| Coordinates | 39.8403100, -88.9548000 |
| Altitude | 205 |
| Country | United States |
#2 Troy
City in Lincoln County, Montana, USA
| Population | 13,341 |
| Coordinates | 38.9794900, -90.9807000 |
| Altitude | 165 |
| Country | United States |
End: Troy (-90.9807, 38.97949)
Estimated Travel Time
Distance: 265 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 05h 29m |
| 40 mph (64.37 km/h) | 04h 07m |
| 50 mph (80.47 km/h) | 03h 17m |
| 60 mph (96.56 km/h) | 02h 44m |
| 70 mph (112.65 km/h) | 02h 21m |
| 80 mph (129 km/h) | 02h 03m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $4.74 | $27.53 | $55.07 |
| Mid-grade | $5.36 | $31.16 | $62.32 |
| Premium | $5.92 | $34.38 | $68.77 |
| Diesel | $6.64 | $38.58 | $77.17 |
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 Illinois · Nov 01, 2026