I‑99 to Williamsport
The former US‑15 freeway from the New York line to Williamsport was officially designated I‑99 on July 30, 2026.
PennDOT I‑99 details ↗Fall south · Spring north
One corridor, two seasons.
The route now includes navigation waypoints at Painted Post, the Harrisburg area, Winchester, Harrisonburg, the Mount Airy area, Charlotte, the Savannah area, and the Brunswick area. They are not automatically overnight stops.
Proposed corridor
About 1,340 miles each way.
| Section | Southbound | Approx. drive | Highway spine | Route purpose |
|---|---|---|---|---|
| 1 | Victor → Corning | ≈108 mi · 2 hr | I‑390 · I‑86 | Reach the Southern Tier and the I‑99 junction |
| 2 | Corning → Harrisburg bypass / I‑81 | ≈163 mi · 3 hr | I‑99 · US‑15 · US‑22/322 | Follow the Susquehanna, then bypass downtown Harrisburg to I‑81 |
| 3 | Harrisburg area → Columbia | ≈587 mi · 9–10 hr | I‑81 · I‑77 | Use the Shenandoah Valley, Fancy Gap, Charlotte, and Columbia corridor |
| 4 | Columbia → Melbourne | ≈481 mi · 7½–8½ hr | I‑26 · I‑95 | Turn to the Atlantic corridor and continue down Florida’s east coast |
Spring reverses all four sections. Times exclude fuel, meals, rest, traffic, weather, construction, and incidents. GPS Guidance can select the next waypoint automatically in either direction. “Area” means the interstate corridor bypasses the named downtown. Live navigation decides the exact connectors on travel day.
Designation and bypass
Three Pennsylvania route numbers, one continuous plan.
US‑15 south
At Williamsport, continue south on US‑15. The roadway remains the natural corridor, but it is not signed I‑99 south of Williamsport.
Pennsylvania 511 ↗US‑22/US‑322 bypass
Near Duncannon, use US‑22/322 east to connect with I‑81 north of downtown Harrisburg, avoiding the slower city approach.
Harrisburg I‑81 information ↗Reverse in spring
Leave I‑81 on US‑22/322 west, join US‑15 north, then transition to I‑99 at Williamsport.
Review route map ↗Four-hour blocks
Choose stops from conditions, not from a promise.
Thirty-minute rest
Before any uninterrupted driving block reaches four hours, leave the car, walk, hydrate, and reset for at least 30 minutes.
Fall southbound
Watch the Southern Tier for lake-effect snow and ice, Fancy Gap for fog, and the coastal states for tropical-weather impacts.
Spring northbound
Watch Florida and the Carolinas for thunderstorms, then reassess mountain fog, cold rain, and late freezing farther north.
Fuel rule
Costco markers appear only where the official warehouse listing showed a gas station when reviewed. Confirm hours and detour distance.
Restaurant rule
Diner-style choices met the 3.8 Google-rating threshold when reviewed. Open the current listing before leaving the route.
GPS Guidance
On an HTTPS phone, choose fall south or spring north, then locate the next mapped Costco or American diner ahead.
Not an overnight plan yet: no city on this page is a required stop. Build travel days around weather, daylight, fatigue, lodging availability, and the stops you choose after reviewing the corridor.
Live travel tools