How far is Seeley Lake, MT from Saint Mary, MO?
The driving distance from Seeley Lake, MT to Saint Mary, MO is about 1686.4 miles (2714 km), with a travel time of about 29h 44m by car.
- The straight-line flight distance is about 1352.2 miles (2176.2 km).
- For a round trip, plan for roughly 59h 28m 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 29h 44m.
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.
Human settlement in Lyman County, South Dakota, United States of America
Route Weather Snapshot
Check the forecast at both ends before you head out.
Widespread Frost
Sunny
Driving Route Map
The map below follows the saved road route between Seeley Lake and Saint Mary.
Turn-by-Turn Driving Directions
Step-by-step road directions between Seeley Lake and Saint Mary.
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1
Start on the route
14.8 mi · 19 min
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2
Turn left
23.8 mi · 26 min
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3
Turn right onto State Highway 141
32.5 mi · 35 min · State Highway 141
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4
Turn sharp right
12.9 mi · 14 min
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5
Turn left
2539 ft · 43 sec
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6
Continue straight
802 ft · 14 sec
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7
Take the ramp straight
1.4 km · 2 min
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8
Merge slight left
45 mi · 42 min
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9
Keep slight right
110.8 mi · 1 hr 51 min
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10
Continue straight
6.9 mi · 6 min
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11
Continue straight
113 mi · 1 hr 53 min
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12
Continue straight
3.1 mi · 4 min
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13
Keep slight right to continue on I 90 East: Sheridan
54 mi · 51 min
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14
Take the exit slight right toward US 212 East: Little Bighorn Battlefield, Broadus
2032 ft · 54 sec
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15
Turn left
42.1 mi · 50 min
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16
Enter the roundabout and take exit 2 toward US Highway 212
66 m · 5 sec · US Highway 212
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17
Exit the roundabout onto US Highway 212
20.1 mi · 24 min · US Highway 212
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18
Continue on Main Street
3072 ft · 2 min · Main Street
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19
Continue on US Highway 212
43.7 mi · 51 min · US Highway 212
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20
Turn right onto Park Avenue
2986 ft · 1 min · Park Avenue
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21
Continue on US Highway 212
93.7 mi · 1 hr 47 min · US Highway 212
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22
Turn right onto North 5th Avenue
2.3 mi · 5 min · North 5th Avenue
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23
Turn left onto SD Highway 34
17.5 mi · 21 min · SD Highway 34
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24
Take the ramp left
10.7 mi · 11 min
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25
Continue straight
23.6 mi · 24 min
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26
Continue straight
338.5 mi · 5 hr 20 min
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27
Take the exit slight right
2349 ft · 57 sec
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28
Merge slight left
342.9 mi · 6 hr 3 min
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29
Merge slight right
2.2 mi · 2 min
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30
Keep slight right to continue on I 435 East: Saint Louis
28 mi · 31 min
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31
Keep slight right to continue on I 70, US 24 West, US 40: Saint Louis, Kansas City, Sports Complex
1500 ft · 23 sec
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32
Keep slight left to continue on I 70 East: Saint Louis
1.2 mi · 2 min
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33
Keep slight left to continue on I 70 East: Saint Louis
143 m · 12 sec
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34
Merge slight left onto George Brett Super Highway
2213 ft · 29 sec · George Brett Super Highway
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35
Continue on Truman/Eisenhower Presidential Highway
2.9 mi · 3 min · Truman/Eisenhower Presidential Highway
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36
Continue on Clifton J. Scott Memorial Highway
1.8 mi · 2 min · Clifton J. Scott Memorial Highway
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37
Continue on Truman/Eisenhower Presidential Highway
2.6 mi · 3 min · Truman/Eisenhower Presidential Highway
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38
Continue on Dwight D. Eisenhower Highway
52.5 mi · 57 min · Dwight D. Eisenhower Highway
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39
Continue on U.S. Submarine Veterans' Memorial Highway
32 mi · 34 min · U.S. Submarine Veterans' Memorial Highway
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40
Keep slight left to continue on U.S. Submarine Veterans' Memorial Highway
22.4 mi · 24 min · U.S. Submarine Veterans' Memorial Highway
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41
Continue on Dwight D. Eisenhower Highway
1.8 mi · 2 min · Dwight D. Eisenhower Highway
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42
Continue on Highway Patrol Sgt. Benjamin Booth Memorial Highway
1.6 mi · 2 min · Highway Patrol Sgt. Benjamin Booth Memorial Highway
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43
Continue on Sheriff Roger I. Wilson Memorial Highway
1.9 mi · 2 min · Sheriff Roger I. Wilson Memorial Highway
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44
Continue on Dwight D. Eisenhower Highway
81 mi · 1 hr 35 min · Dwight D. Eisenhower Highway
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45
Take the exit slight right toward I 64 East, US 40 East, US 61 South: Chesterfield
1567 ft · 33 sec
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46
Merge slight left onto Avenue of the Saints
25.1 mi · 31 min · Avenue of the Saints
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47
Take the exit slight right toward I 270: Chicago, Memphis
1829 ft · 39 sec
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48
Keep slight right to continue on I 270 South: Memphis
1691 ft · 31 sec
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49
Merge slight left
11.5 mi · 14 min
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50
Take the exit slight right toward I 55, US 61, US 67: Saint Louis, Memphis, Lemay Ferry Road
1911 ft · 27 sec
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51
Keep slight right to continue on I 55 South: Memphis
2031 ft · 44 sec
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52
Merge slight left onto Rosa Parks Highway
1.5 mi · 2 min · Rosa Parks Highway
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53
Continue on Officer Thomas G. Smith, Jr. Memorial Highway
1.8 mi · 2 min · Officer Thomas G. Smith, Jr. Memorial Highway
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54
Continue on Police Officer Steven Jarvis Memorial Highway
42.6 mi · 46 min · Police Officer Steven Jarvis Memorial Highway
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55
Take the exit slight right toward MO 32, MO A, MO B: Sainte Genevieve, Farmington
952 ft · 21 sec
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56
Turn left
4.4 mi · 7 min
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57
Keep slight right
1680 ft · 30 sec
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58
Turn slight right onto Sainte Genevieve Drive
8.4 mi · 12 min · Sainte Genevieve Drive
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59
Continue on 2nd Street
2510 ft · 45 sec · 2nd Street
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60
Turn right onto 4th Street
31 m · 5 sec · 4th Street
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61
Arrive at your destination
0 m · 1 sec · 4th Street
Car Route Details
A richer read on the saved driving route between Seeley Lake and Saint Mary.
Long-distance drive
This route is long enough that fuel, rest stops, weather, and timing matter more than any single maneuver.
SD Highway 34
Merge slight left
343 mi · 06h 03m
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.
Widespread Frost leaving Seeley Lake and Sunny near Saint Mary.
Trip Questions
Direct answers travelers usually want before committing to the drive.
How long does it take to drive from Seeley Lake to Saint Mary?
The road trip is about 1686.4 miles (2714 km) and usually takes 29h 44m 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?
Presho is a useful midpoint, sitting about 842 miles from Seeley Lake and 844.4 miles from Saint Mary.
How much longer is the road route than the straight-line distance?
The direct path is about 1352.2 miles (2176.2 km), while the road route adds roughly 334.2 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 $266.90 one way or $533.80 round trip. Estimated CO2 is about 528.9 kg one way.
Do you cross a time zone on this route?
Yes. There is about a 1 hour time difference between Seeley Lake and Saint Mary, so arrival and return times should be read in local time.
What should you check before leaving?
Before you leave, expect Widespread Frost around Seeley Lake and Sunny near Saint Mary.
Flight Path Map
This map shows the direct air route between Seeley Lake and Saint Mary. Straight-line distance: 1352.24 mi (2176.22 km).
#1 Seeley Lake
Census designated place in Montana, USA
| Population | 1,659 |
| Coordinates | 47.1793800, -113.4845200 |
| Altitude | 1225 |
| Country | United States |
#2 Saint Mary
City in Missouri, United States
| Population | 345 |
| Coordinates | 37.8789400, -89.9492800 |
| Altitude | 119 |
| Country | United States |
End: Saint Mary (-89.94928, 37.87894)
Estimated Travel Time
Distance: 2714 km by road
| Speed | Time |
|---|---|
| 30 mph (48.3 km/h) | 56h 11m |
| 40 mph (64.37 km/h) | 42h 09m |
| 50 mph (80.47 km/h) | 33h 43m |
| 60 mph (96.56 km/h) | 28h 06m |
| 70 mph (112.65 km/h) | 24h 05m |
| 80 mph (129 km/h) | 21h 02m |
Fuel, Round Trip and CO2
Estimated fuel cost and emissions for this route.
| Fuel | $/gal | One way | Round trip |
|---|---|---|---|
| Regular gas | $4.49 | $266.90 | $533.80 |
| Mid-grade | $4.81 | $286.48 | $572.96 |
| Premium | $5.19 | $308.98 | $617.95 |
| Diesel | $6.17 | $367.00 | $734.00 |
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 Montana · Oct 17, 2026