Saint Marys to Harrisburg is 162.4 miles and takes about 3h 37m via General Potter Highway and Keystone Shortway, with a fuel budget near $27 and enough daylight to finish in a day. This drive travels within Pennsylvania, moving from the Northeast region towards the central part of the state. Expect a route that involves frequent turns and a local feel for much of the journey, rather than a straightforward interstate cruise. It's a solid option for a single-day trip, offering a manageable distance with a relatively short estimated drive time.
Trip Pace
Same-day drive is realistic
A same-day return is realistic if you keep stops short.
Break Rhythm
1 planned break
A short stop every 2 to 3 hours is enough for this drive.
Midpoint
81.2 miles from Saint Marys, PA
A natural place for your longest stop of the day
, about 1h 51m into the drive
.
Main Roads
Road
Distance
Duration
General Potter Highway
78.2 mi
1h 40m
Keystone Shortway
11.7 mi
12m
Million Dollar Highway
10.9 mi
16m
28th Division Highway
8.6 mi
9m
State Park Road
8.1 mi
14m
Bennetts Valley Highway
7.9 mi
12m
Philipsburg Bigler Highway
7.1 mi
8m
Mount Nittany Expressway
6.2 mi
8m
Longest stretch:
General Potter Highway
— 78.2 mi, about 1h 40m
Turn-by-Turn Driving Directions
Step-by-step road directions between Saint Marys, PA and Harrisburg, PA.
1
Start on PA 120; PA 255
45 ft·1 sec·Railroad Street
2
Turn left onto PA 120; PA 255
223 ft·4 sec·South Michael Street
3
Turn slight left onto PA 120
0.2 mi·22 sec·PA 120
4
Continue on PA 255
11 mi·16 min·Million Dollar Highway
5
Continue on PA 255
7.9 mi·12 min·Bennetts Valley Highway
6
Turn left onto PA 153
8.1 mi·14 min·State Park Road
7
Turn left
0.3 mi·40 sec
8
Merge onto I 80
12 mi·12 min·Keystone Shortway
9
Take the exit
0.3 mi·42 sec
Toward PA 970 to US 322: Woodland, Shawville
10
Merge onto PA 970
1.4 mi·1 min·Shawville Highway
Use the straight lane.
11
Turn left onto US 322
2.8 mi·3 min·Woodland Bigler Highway
12
Continue on US 322
7.1 mi·8 min·Philipsburg Bigler Highway
13
Continue on US 322
0.3 mi·23 sec·North Front Street
14
Continue on US 322; PA 53
0.1 mi·15 sec·North Centre Street
15
Turn left onto US 322
1.1 mi·2 min·Railroad Street
16
Continue on US 322
5.9 mi·8 min·Port Matilda Highway
17
Turn slight right onto US 322
2.2 mi·3 min·Upper Flat Rock Road
18
Continue on US 322
1.8 mi·2 min·Flat Rock Road
19
Continue on US 322
8.6 mi·9 min·28th Division Highway
Toward US 322 East: State College
20
Keep slight left at fork onto I 99; US 220; US 322
4.0 mi·4 min·I 99; US 220; US 322
Use the straight lane.
21
Keep slight right at fork onto US 322
6.2 mi·8 min·Mount Nittany Expressway
Exit 73Toward US 322 East: Penn State University, State College
22
Continue on US 322; PA 144 Truck
2.6 mi·4 min·Boal Avenue
Use the straight lane.
23
Continue on US 322; PA 144 Truck
78 mi·1 hr 40 min·General Potter Highway
Use the straight / slight right lanes.
24
Turn right onto Herr Street
0.3 mi·44 sec·Herr Street
25
Turn right onto North 7th Street
0.3 mi·46 sec·North 7th Street
26
Arrive at destination
North 7th Street
Trip Plan
Given the estimated 3h 37m drive time and 162.4-mile distance, this trip is well-suited for a single day, making flexibility your advantage. Aim to depart in the morning to take full advantage of daylight, especially since much of the route is local. There's one recommended stop, so plan to use it for a break or to refuel if needed, as the longest stretch without significant interruption is 78.2 miles. Keep an eye on your fuel gauge, as the $27 estimated fuel cost suggests a moderate consumption, and local roads can sometimes be more spread out between services than major interstates.
Morning Departure
An early start around 7-8 AM gets you there with plenty of daylight left.
Evening Departure
A late afternoon start means arriving after dark. Morning is better.
You can normally do this drive in one day.
Plan roughly 1 meaningful break for fuel, food, and rest.
The halfway point lands around 81.2 miles from Saint Marys, PA, or about 1h 51m into the drive.
The longest continuous stretch on this route runs about 78.2 miles.
This is a comfortable same-day trip.
Departure
Before you leave
Start with fuel, water, and navigation already sorted so the first hour feels easy.
First stop
Around 36 miles or 53m in
Use this first pause for coffee, a restroom break, and a quick traffic check ahead.
Halfway reset
Around 81.2 miles or 1h 51m in
This is the best place for your longest stop, a real meal, and a full fuel check.
Final approach
Final hour starts around 2h 58m
Traffic, exits, and arrival timing usually matter more near Harrisburg, PA than in the middle of the route.
Before You Leave
+
Open the route before leaving Saint Marys, PA 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.
Day 1
Settle into the route from Saint Marys, PA
This is one driving day of about 162.4 miles and 3h 37m.
Your first comfortable stop window is around 36 miles from Saint Marys, PA.
This route can stay practical as a one-day drive if traffic stays reasonable.
Plan about 1 real break rather than only quick fuel stops.
The longest stretch is on General Potter Highway for about 78.2 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 12
5 decision points cluster between mile 0 and 74.8 — GPS handles the exact turns, but know they're coming. Your lane choice matters more than the turn itself.
4
0 mi into trip|~0m in|PA 120; PA 255 / South Michael Street
Turn left onto PA 120; PA 255 / South Michael Street
Navigation decision point
5
39.2 mi into trip|~57m in
Take the exit toward PA 970 to US 322: Woodland, Shawville
Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one
Toward PA 970 to US 322: Woodland, Shawville
5
39.5 mi into trip|~57m in|PA 970 / Shawville Highway
Merge onto PA 970 / Shawville Highway
Merge point - match speed before joining. Lane positioning matters here
Use the straight lane.
6
70.9 mi into trip|~1h 37m in|I 99; US 220; US 322
Keep slight left at fork onto I 99; US 220; US 322
Highway fork - watch signs carefully. Lane positioning matters here
Use the straight lane.
7
74.8 mi into trip|~1h 42m in|US 322 / Mount Nittany Expressway
Keep slight right at fork onto US 322 / Mount Nittany Expressway toward US 322 East: Penn State University, State College
Highway fork - watch signs carefully. Multiple destination signs - pick the right one
Exit 73
Toward US 322 East: Penn State University, Stat...
Fuel & Cost
Regular Gas
$26.92 one way
$53.85 round trip
$4.21/gal25.4 MPG avg57 kg CO2
Fuel Type
$/gal
One Way
Round Trip
midgrade
$4.61
$29.49
$58.98
premium
$4.93
$31.50
$62.99
diesel
$5.61
$35.86
$71.71
No toll roads detected on this route.
Estimated Trip Cost (one way, 1 person)
Fuel
$27
Meals
$25–$50
Total
$52–$77
Rough estimate based on US averages. Hotel $80–$140/night, meals $25–$50/day.
Estimated CO2 emission: 56.8 kg one way.
Prices: EIA weekly data, 2026-04-13.
Driving Electric?
About $17 in charging
· 0 stops
· 67% less CO2
Vehicle Type
kWh
Stops
DC Fast
Home Charge
Average EV
48.7
0
$17.05
$7.80
Efficient EV
40.6
0
$14.21
$6.50
EV Truck/SUV
65
0
$22.74
$10.39
Gas CO2
57 kg
EV CO2
19 kg (67% less)
This trip is well within single-charge range for most EVs. No charging stops needed if you start fully charged.
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 Apr 19, 2026
Origin
Saint Marys, PA
Morning
in Saint Marys on Sunday
Local time
6:24 AM
EDT
Current temp
68°F
Unavailable
Live forecast
Destination
Harrisburg, PA
Morning
in Harrisburg on Sunday
Local time
6:24 AM
EDT
Current temp
64°F
Unavailable
Live forecast
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.
Time zone
Same local time
Origin and destination are on the same clock, so arrival timing is easier to judge at a glance.
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
3h 37m on the road
Use the two city cards together: check the sky where you start, then compare it with the local time and temperature at arrival.
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.
Carlisle Federal Indian Boarding School National Monument
National Monument
More than 7,800 children from 140 Tribes went to the Carlisle School from 1879 to 1918. The National Park Service will collaborate with families, affiliated Tribal Nations, the US Army, historians, an...
15 mi from route
~38 min detour
Free
near mile 151.2
The Appalachian Trail is a 2,190+ mile long public footpath that traverses the scenic, wooded, pastoral, wild, and culturally resonant lands of the Appalachian Mountains. Conceived in 1921, built by p...
25 mi from route
~63 min detour
Free
near mile 156.8
Park data from the National Park Service API. Alerts update every 2 hours.
More Details
What kind of drive is this?
This route is characterized as a 'turn-heavy local drive,' indicated by a highway share of only 6%. While it includes some highway stretches like the Keystone Shortway, a significant portion follows local roads, potentially meaning more frequent intersections and changes in speed limits. The longest uninterrupted stretch you'll encounter is 78.2 miles on General Potter Highway, which might offer a more consistent pace before transitioning back to more winding sections. Be prepared for a dynamic driving experience that requires attention to navigation and road conditions.
Only 6% highway — the rest is turn-by-turn surface driving.
26 navigation steps total — most of the decisions cluster near the start and finish.
Longest single stretch: 78.2 mi on General Potter Highway.
How Hard Is This Drive?
6/10
Expect a hands-on drive with frequent turns and local roads rather than long highway stretches. You will hit about 12 points where you need to pay attention to lane position or signs. The trickiest moment comes early in the drive near PA 120; PA 255 / South Michael Street.
Driving Effort6/10
Moderate - straightforward overall, but long enough or busy enough to require pacing
Balances navigation complexity with total wheel time.
This drive requires moderate attention. Across 162.4 miles you will encounter 12 spots where lane choice or exit timing matters. Not difficult for experienced highway drivers, but worth previewing the tricky sections before you go.
Where does it get tricky?
The main spots that need attention: near the start (PA 120; PA 255 / South Michael Street): Navigation decision point; at 39.2 miles: Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one; at 39.5 miles (PA 970 / Shawville Highway): Merge point - match speed before joining. Lane positioning matters here.
Towns Mentioned on Route Signs
Based on OSRM destination-sign hints, not a full list of every settlement the road passes.
Between Saint Marys, PA and Harrisburg, PA, road signs point toward Shawville and State College.
Harrisburg is the capital and 4th-largest metropolitan area of Pennsylvania, with a metro population of 592,000 people in 2020. Harrisburg is known as the host city of the Pennsylvania Farm Show, the largest free indoor agriculture exposition in the United States, the largest annual outdoor sports show in North America, an auto show, which features a large static display of new and classic cars, and Motorama, a two-day event consisting of a car show, motocross racing, and remote control car racing.
Doable as a same-day drive at 3h 37m. Total distance: 162.4 miles.
Family Friendly
Moderate complexity with 1 natural rest stops along the way.
Solo Traveler
3h 37m drive, comfortable solo distance.
Scenic Drive
Mostly surface roads route profile with national parks nearby.
Frequently Asked Questions
The longest stretch is about 78.2 miles on General Potter Highway. The full list of main roads is in the Roads section above.
We did not find dedicated rest areas on this route. For a drive this long, plan bathroom and stretch breaks around gas stations, fast-food stops, or small-town downtowns — check the Nearby Places section for options.
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 Harrisburg, PA 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 1 meaningful breaks. Dedicated rest areas are limited, so plan gas or food stops as your bathroom breaks.
The main spots that need attention: near the start (PA 120; PA 255 / South Michael Street): Navigation decision point; at 39.2 miles: Exit ramp - move to the correct lane early. Multiple destination signs - pick the right one; at 39.5 miles (PA 970 / Shawville Highway): Merge point - match speed before joining. Lane positioning matters here.
Yes — Carlisle Federal Indian Boarding School National Monument and Appalachian National Scenic Trail. See the National Parks section for detour distances and tips on detours.
Possible but tiring. At 3.6 hours each way, an in-and-out day trip would put you behind the wheel for 7.2 hours — manageable with a long break at Harrisburg, PA, but most travelers stay overnight.
