How far is Decatur, IL from Alton, IL?
The driving distance from Decatur, IL to Alton, IL is about 107.5 miles (173 km), with a travel time of about 02h 24m by car.
- The straight-line flight distance is about 92.8 miles (149.4 km).
- For a round trip, plan for roughly 04h 49m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 8:00 AM to 10:00 AM CDT.
Reverse, save, or send this route
This route works well as a day trip with time at the destination. Copy the route link, send it to another device, or print a clean version before you head out.
This route works well as a day trip with time at the destination.
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 02h 24m.
A morning start gives you useful time at the destination and keeps the return out of the late evening.
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.
Township in Montgomery County, Illinois
Route Weather Snapshot
Check the forecast at both ends before you head out.
Slight Chance Showers And Thunderstorms
Chance Showers And Thunderstorms
Driving Route Map
The map below follows the saved road route between Decatur and Alton.
Turn-by-Turn Driving Directions
Step-by-step road directions between Decatur and Alton.
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1
Start on East Wood Street
91 m · 16 sec · East Wood Street
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2
Turn left onto South Main Street
1.3 mi · 2 min · South Main Street
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3
Turn right onto West South Side Drive
1.5 km · 1 min · West South Side Drive
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4
Turn left onto South Taylorville Road
12.9 mi · 15 min · South Taylorville Road
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5
Continue on County Road 2080 E
18.4 mi · 23 min · County Road 2080 E
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6
Continue on County Road 975 N
3056 ft · 52 sec · County Road 975 N
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7
Continue on Sarpy Street
12.2 mi · 21 min · Sarpy Street
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8
Continue on Front Street
7.6 mi · 11 min · Front Street
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9
Turn left onto I 55 South: East Saint Louis
1822 ft · 44 sec
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10
Merge slight left
32.9 mi · 35 min
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11
Take the exit slight right toward IL 140: Alton, Greenville
1756 ft · 43 sec
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12
Turn right onto East State Street
1 km · 1 min · East State Street
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13
Continue on State Route 140
9.6 mi · 13 min · State Route 140
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14
Continue on East Bethalto Drive
1.8 mi · 4 min · East Bethalto Drive
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15
Continue on East MacArthur Drive
1.4 mi · 3 min · East MacArthur Drive
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16
Continue on West Macarthur Drive
1.3 mi · 2 min · West Macarthur Drive
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17
Continue on College Avenue
3.6 mi · 6 min · College Avenue
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18
Enter the roundabout and take exit 3 toward College Avenue
121 m · 8 sec · College Avenue
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19
Exit the roundabout onto College Avenue
1355 ft · 27 sec · College Avenue
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20
Turn left onto Martin Luther King Drive
1.5 km · 1 min · Martin Luther King Drive
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21
Continue on Piasa Street
1877 ft · 37 sec · Piasa Street
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22
Turn left onto West 3rd Street
662 ft · 31 sec · West 3rd Street
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23
Turn right onto Alby Street
36 m · 5 sec · Alby Street
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24
Arrive at your destination
0 m · 1 sec · Alby Street
Car Route Details
A richer read on the saved driving route between Decatur and Alton.
Straightforward drive
The saved road route has a manageable number of maneuvers and should be easy to follow with normal attention to signs.
I 55 South
Merge slight left
32.9 mi · 00h 35m
Route Summary
A quick read on whether this route feels easy, ambitious, or worth planning around.
A comfortable day-trip route
This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.
Slight Chance Showers And Thunderstorms leaving Decatur and Chance Showers And Thunderstorms near Alton.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Decatur to Alton?
The road trip is about 107.5 miles (173 km) and usually takes 02h 24m in normal driving conditions.
Is this a same-day trip or an overnight route?
This route works well as a day trip. You can leave in the morning, spend meaningful time at the destination, and still return the same day.
What is the halfway point on this route?
Zanesville is a useful midpoint, sitting about 53.7 miles from Decatur and 53.7 miles from Alton.
How much longer is the road route than the straight-line distance?
The direct path is about 92.8 miles (149.4 km), while the road route adds roughly 14.7 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 8:00 AM to 10:00 AM CDT. If you want a more comfortable same-day return, try to leave by 1:40 PM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $14.29 one way or $28.58 round trip. Estimated CO2 is about 33.7 kg one way.
What should you check before leaving?
Before you leave, expect Slight Chance Showers And Thunderstorms around Decatur and Chance Showers And Thunderstorms near Alton.
Stop Ideas Near Zanesville
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 Zanesville.
Carlinville
Springfield station
Alton
Gateway Transportation Center
Flight Path Map
This map shows the direct air route between Decatur and Alton. Straight-line distance: 92.84 mi (149.41 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 Alton
City in Madison County, Illinois, United States
| Population | 26,049 |
| Coordinates | 38.8906000, -90.1842800 |
| Altitude | 150 |
| Country | United States |
End: Alton (-90.18428, 38.8906)
Estimated Travel Time
Distance: 173 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 03h 34m |
| 40 mph (64.37 km/h) | 02h 41m |
| 50 mph (80.47 km/h) | 02h 09m |
| 60 mph (96.56 km/h) | 01h 47m |
| 70 mph (112.65 km/h) | 01h 32m |
| 80 mph (129 km/h) | 01h 20m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $14.29 | $28.58 |
| Mid-grade | $4.25 | $16.12 | $32.24 |
| Premium | $4.65 | $17.64 | $35.28 |
| Diesel | $5.30 | $20.10 | $40.20 |
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 · Apr 16, 2026
Distance to Other Cities
Planning a road trip? See the full trip guide on Trip.ovh — stops, fuel costs, weather, and departure timing.