How far is Decatur, IL from Flagg, IL?
The driving distance from Decatur, IL to Flagg, IL is about 159.8 miles (257.1 km), with a travel time of about 03h 10m by car.
- The straight-line flight distance is about 142.4 miles (229.1 km).
- For a round trip, plan for roughly 06h 20m of driving time before adding stops, traffic, or weather delays.
- A comfortable departure window is usually 6:00 AM to 8:00 AM CDT.
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 10m.
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.
City in Woodford County, Illinois, United States
Route Weather Snapshot
Check the forecast at both ends before you head out.
Mostly Sunny
Driving Route Map
The map below follows the saved road route between Decatur and Flagg.
Turn-by-Turn Driving Directions
Step-by-step road directions between Decatur and Flagg.
-
1
Start on East Wood Street
155 m · 23 sec · East Wood Street
-
2
Turn left onto South Franklin Street
2129 ft · 46 sec · South Franklin Street
-
3
Continue on North Water Street
27.4 mi · 37 min · North Water Street
-
4
Continue on North 1450 East Road
14.7 mi · 18 min · North 1450 East Road
-
5
Take the exit slight right toward I 74 West, US 51 North: Peoria, Rockford
8.9 mi · 10 min
-
6
Take the exit slight right toward I 39 North: Rockford
98.5 mi · 1 hr 46 min
-
7
Take the exit slight right toward I 88 West Toll: Moline, Rock Island
2323 ft · 1 min
-
8
Merge slight left onto Ronald Reagan Memorial Tollway
2.1 mi · 2 min · Ronald Reagan Memorial Tollway
-
9
Take the exit slight right toward IL 251: Rochelle, Mendota
2006 ft · 49 sec
-
10
Turn right
1.4 mi · 2 min
-
11
Turn right onto 4th Avenue
103 m · 10 sec · 4th Avenue
-
12
Turn right onto North 6th Street
120 m · 9 sec · North 6th Street
-
13
Turn right onto Lincoln Avenue
4.1 mi · 7 min · Lincoln Avenue
-
14
Turn left onto South Grange Road
1.1 mi · 4 min · South Grange Road
-
15
Turn left onto East Titus Road
19 m · 3 sec · East Titus Road
-
16
Arrive at your destination
0 m · 1 sec · East Titus Road
Car Route Details
A richer read on the saved driving route between Decatur and Flagg.
Highway-focused drive
Most of the mileage stays on named highways, so the important moments are ramps, exits, merges, and the final local approach.
I 39 North
Take the exit slight right toward I 39 North: Rockford
98.5 mi · 01h 46m
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.
Sunny leaving Decatur and Mostly Sunny near Flagg.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Decatur to Flagg?
The road trip is about 159.8 miles (257.1 km) and usually takes 03h 10m 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?
Minonk is a useful midpoint, sitting about 80 miles from Decatur and 79.8 miles from Flagg.
How much longer is the road route than the straight-line distance?
The direct path is about 142.4 miles (229.1 km), while the road route adds roughly 17.4 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 8:00 AM CDT. If you want a more comfortable same-day return, try to leave by 10:40 AM CDT.
How much will gas cost for this route?
Using about 28.3 MPG, regular gas is estimated at $21.27 one way or $42.54 round trip. Estimated CO2 is about 50.1 kg one way.
What should you check before leaving?
Before you leave, expect Sunny around Decatur and Mostly Sunny near Flagg.
Stop Ideas Near Minonk
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 Minonk.
Pontiac station
Uptown Station
Dwight station
Peoria, Illinois
Flight Path Map
This map shows the direct air route between Decatur and Flagg. Straight-line distance: 142.36 mi (229.1 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 Flagg
City in Illinois, United States of America
| Population | 12,745 |
| Coordinates | 41.8958600, -89.1409300 |
| Altitude | 238 |
| Country | United States |
End: Flagg (-89.14093, 41.89586)
Estimated Travel Time
Distance: 257 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 05h 19m |
| 40 mph (64.37 km/h) | 03h 59m |
| 50 mph (80.47 km/h) | 03h 11m |
| 60 mph (96.56 km/h) | 02h 39m |
| 70 mph (112.65 km/h) | 02h 16m |
| 80 mph (129 km/h) | 01h 59m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $3.77 | $21.27 | $42.54 |
| Mid-grade | $4.25 | $23.99 | $47.97 |
| Premium | $4.65 | $26.25 | $52.50 |
| Diesel | $5.30 | $29.91 | $59.83 |
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 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.