Interstate 99

Overview

Interstate 99 is a rural freeway traveling northward through central Pennsylvania from Bedford near the Pennsylvania Turnpike (I-70/76) to I-80 near Bellefonte. A second section overlays U.S. 15 from I-180 and U.S. 220 in Williamsport northward 62 miles to Interstate 86 at Painted Post, New York. The section between Bedford and State College is also known as the Appalachian Thruway and the Bud Shuster Byway. It was the first Interstate highway to have its designation written into law (National Highway Designation Act of 1995). The designations for several other Interstates, including I-66 in Kentucky, I-86 in New York, and I-69 in Texas, were subsequently written into law.

Ultimately, the separate sections of I-99 will connect via U.S. 220 from I-80 east to Lock Haven and Williamsport. The section of U.S. 15 leading north from the Pennsylvania state line near Lawrenceville to I-86 at Painted Post, NY was designated as Interstate 99 on June 27, 2014 (Ek, 2014). The remainder of U.S. 15 south to I-180 became part of I-99 on July 30, 2026 (PennDOT, 2026).

Speed limits along Interstate 99 increased to 70 miles per hour (mph) on May 3, 2016 from mile marker 34 in Blair County to Exit 68 in Centre County, and from mile marker zero at the PA Turnpike in Bedford County to Exit 28 in Blair County (Kibler, 2016). Additionally a 49 mile stretch of U.S. 15, from PA 14 in Lycoming County to the New York state line, was increased to 70 mph. PennDOT announced increases on these stretches among nearly 1,000 miles of Turnpike and Interstate highways statewide on May 2, 2016 (Alexandersen, 2016).

Located east of I-79 and west of I-81, I-99 falls outside the standard numbering convention outlined for Interstate highways. Under the orderly system, odd numbered Interstates increase in number from I-5 on the West Coast eastward to the Atlantic seaboard. While central Pennsylvania is pretty far east, it is still well away from the Atlantic Ocean. Several north-south routes, including I-81, I-83, I-87, I-89, I-91, I-93, I-95 and I-97 all lie east of Interstate 99. Congressman Bud Shuster both determined the number for the Appalachian Thruway and was responsible for writing Interstate 99's designation into the 1995 National Highway Designation Act.

Interstate 80/99 Interchange

A $35 million Infrastructure for Rebuilding America Grant (INFRA) was awarded to the Pennsylvania Department of Transportation toward funding construction of a high speed interchange linking I-99 with I-80 near Bellefonte on June 5, 2018. Estimated to cost around $200 million (Corso, 2019), the new ramp system replaces the parclo A2 interchange at U.S. 220 and PA 26 that joins the north end of I-99 with Interstate 80.

The overall project consists of three sections. Underway in June 2020, initial construction built a new local access interchange connecting I-80 with PA 26 to the east of the exchange with I-99. This exchange was completed in mid December 2022 (PennDOT, n.d.).

The Jacksonville Road Betterment (26/147) project realigns and expands PA 26 along Jacksonville Road. Costing $8.6 million, work anticipated through November 2026 finally got underway in November 2024 (PennDOT, 2025a).

The remainder of work building the three-wye interchange for I-80/99 got underway in September 2024. The $259 million project extends to September 2030 (PennDOT, 2025b). Previously estimated to cost $175 million, work was originally anticipated to run through December 2025 (Corso, 2019).

High Priority Corridor

Interstate 99 in central Pennsylvania is part of High Priority Corridor 9: Appalachian Thruway Corridor.

Parallel U.S. Routes

Interstate 99 between Bedford and Bellefonte overlaps with U.S. 220 for its entirety, and it will continue along U.S. 220 until reaching U.S. 15 at Williamsport. Interstate 99 is currently cosigned with U.S. 15 from Williamsport, Pennsylvania northward to their shared end point at I-86 near Corning, New York.

History

The initial section of the U.S. 220 freeway opened south from Bedford Township to U.S. 30 in 1969. The remainder of the route north through Bedford and Blair Counties was built in the 1970s and 1980s (Joseph, 2008). $138 million in upgrades to Interstate standards took place along the U.S. 220 freeway north from Bedford to Bald Eagle to 1989 (Alaya, 1995). Discussions followed in the early 1990s to extend the freeway north 30 miles through Centre County to I-80 near Bellefonte (Joseph, 2008). Spearheaded by U.S. Rep. Bud Shuster, R-Everett, the first signs for I-99 were unveiled on December 1, 1995 near the interchange with 17th Street in Altoona. The designation of 35 miles of U.S. 220 between Bedford and Altoona was included in the National Highway System Designation Act signed by President Clinton on November 28, 1995. The bill added 161,000 miles of roads into the National Highway System, which gained priority for federal funding. The law provided $118 million of the estimated $370 million needed at the time to complete the 30 mile long I-99 corridor north from Bald Eagle through State College (Alaya, 1995).

Three sections were proposed in 1995 to complete Interstate 99 north from Bald Eagle to the Bellefonte Bypass (PA 26). The 17.5 mile long segment from Bald Eagle to U.S. 322, including a bypass of Port Matilda, was estimated to cost $365 million. This section stretches across Skytop Mountain to join the Mount Nitanny Expressway (U.S. 322 around State College) (Alaya, 1995).

The second section involved upgrading U.S. 322 between Scotia Road and Park Avenue Extension, and a relocation of PA 26. Also included was a new eight mile alignment linking U.S. 322 at Park Avenue Extension with the Bellefonte Bypass. Expansion of the four mile long Bellefonte Bypass in Spring Township represented the last section at a cost of $180 million (Alaya, 1995).

An Environmental Impact Statement for I-99 over Bald Eagle Ridge was completed by the Pennsylvania Department of Transportation (PennDOT) in 1996. The approval of TEA-21 by Congress in 1998 included a two sentence rider by U.S. Rep. Bud Shuster that eliminated federal oversight of Interstate 99 (Joseph, 2008). Subsequent approval for I-99 between Bedford and Bald Eagle was approved by the American Association of State Highway and Transportation Officials (AASHTO) Route Numbering Subcommittee on November 6, 1998.

Land clearing for I-99 commenced in 1999 near Bellefonte and a $39 million contract to build 1.3 miles of new roadway over Bald Eagle Ridge at Skytop was awarded in 2001 (Joseph, 2008). Meanwhile the eight mile link between State College and Interstate 80 opened to motorists on November 25, 2002. Costing $200 million to build, the segment includes six interchanges (Joseph, 2002).

Construction of the route west of State College, known as the "Skytop" section, was hampered with delays due to environmental concerns associated with acid rock--sandstone laced with pyrite. Without measures in place to prevent contamination of streams and ground water, crews in 2003 unearthed a million cubic years of the pyrite-laced sandstone, which when exposed to air and water creates sulfuric acid. $82.7 million in work ensued in 2004 to contain the runoff and clean up the site. This delayed work from an anticipated 2006 completion date (Joseph, 2008).

Following years of delays, the 14 mile link between Bald Eagle and Patton Township opened on December 17, 2007, with the exception of the 1.4 mile long section at the acid-rock drainage cleanup site on Skytop Mountain (Joseph, 2007).

The section between Skytop and State College was finally completed on November 17, 2008, when eight miles of the freeway southbound opened. Total costs for this section of I-99 was $702 million. This left the work on the planned high speed interchange joining I-80 and I-99. Projected to cost $146 million in 2008, redesign of the exchange was undertaken to avoid excavating too much pyrite (Joseph, 2008).

The remainder of Interstate 99 in Pennsylvania was a future route with signs proclaiming its extension along U.S. 220 to Lock Haven and Williamsport, then northward along U.S. 15 to the state line at Lawrenceville. This changed on July 30, 2026 when Interstate 99 signage was unveiled along U.S. 15 between I-180 and the New York state line.

Several decades of construction upgraded U.S. 15 between Williamsport and Painted Post to limited access standards. A new freeway for U.S. 15, from Tioga, Pennsylvania north to Lindley, New York, opened after a ribbon cutting ceremony held on October 1, 2008. The seven mile segment cost $118.7 million to build (Affissio, 2008). See photos of the roadway on John Walter's site.

Interstate 99 in New York

Within Steuben County and the village of Painted Posted, New York, construction to upgrade the exchange between the Southern Tier Expressway and U.S. 15 (Interstate 99) started in November 2003. The first phase of work involved a $41 million project to bring U.S. 15 up to Interstate standards and to add a diamond interchange with NY 417 (Addison Road / Hamilton Street). The second phase, costing $11 million, rebuilt a two mile stretch of I-86 by the north end of U.S. 15 (Smith, 2004a).

The final phase of the Painted Post Interchange project added flyovers for the eventual freeway leading U.S. 15 south to Presho and reconstructed Hamilton Street and Robert Dann Drive. The $70 million project commenced in Spring 2005 and was scheduled for a Fall 2007 completion (Smith, 2004b). Delays pushed work to a ribbon cutting ceremony held on the morning of August 13, 2008. Total costs for the three phase project topped out at $141 million (Smith, 2008).

Road construction on the final five mile portion, north from Watson Creek Road at Lindley to Presho, began in August 2012. Taking place as $46 million in ground work wrapped up, the $31 million project included building six bridges (Zick, 2012). Completion took place on October 8, 2013. Overall costs to build Interstate 99 in New York were $235 million (Post, 2013).

North End - NY Section  ‐ Painted Post, NY

North at

Continuing past NY 417 (Hamilton Street) in Gang Mills, I-99/U.S. 15 advance one mile north to the separation of flyovers for I-86/NY 17. 03/25/23

East at

An auxiliary lane accompanies I-86/NY 17 east from NY 415 (Exit 43) to the interchange complex (Exits 44 A/B) with I-99/U.S. 15 south and NY 417 (Hamilton Street) west. 01/18/17

West at

A flyover links NY 352 on Denison Parkway with NY 417 (Hamilton Street) beside I-86/NY 17 west into the directional T interchange (Exit 44 A) with I-99/U.S. 15 south. 03/25/23

Former South End - NY Section  ‐ Pennsylvania state at Lawrenceville

Past Views Gallery (Tap to Expand / Collapse Section)

South

Prior to July 30, 2026, Interstate 99 concluded southbound along U.S. 15 at the state line by Lawrenceville, Pennsylvania. 03/25/23

North

The freeway along U.S. 15 previously became part of Interstate 99 north into the town of Lindley, New York. 03/25/23

North End - PA Section  ‐ near Bellefonte, PA

North at

An end shield for the southern section of Interstate 99 precedes the intersection with Jacksonville Road. 07/25/24

South at

PA 26 (Jacksonville Road) south ahead of the exchange with Interstate 80, I-99 south and U.S. 220 north. 11/30/-1

East at

Exit 161 departs Interstate 80 east for I-99/U.S. 220 south to State College and Altoona and PA 26 (Jacksonville Road) east to Jacksonville. 07/25/24

Historic Northern End  ‐ Bald Eagle, PA

Past Views Gallery (Tap to Expand / Collapse Section)

at

PA 350 (7 Stars Road) westbound combined with U.S. 220 at a T-intersection just north of the temporary freeway end of I-99. Photo by Tim Reichard (04/07/02).

South End  ‐ Bedford Township, PA

South at

An end shield for I-99 stands ahead of the trumpet interchange (Exit 1) with the access road linking U.S. 220 with U.S. 220 Business. 07/14/24

North at

U.S. 30 passes through the borough of Bedford along a freeway south of the PA Turnpike (I-70/76). The succeeding exit along U.S. 220 north is the first along Interstate 99. 07/25/25

East at

Exit 146 departs following the Bugle Road and U.S. 220 freeway overpasses for U.S. 220 Business. U.S. 220 Business leads motorists north 0.3 miles to an access road linking with I-99 north to Altoona and U.S. 220 south to Cumberland, Maryland. A similar at-grade connection links the PA Turnpike with I-81 at Carlisle. Photo by Chris and Amber Lokken (06/24/08).

West at

Entering the trumpet interchange (Exit 146) with U.S. 220 Business on I-70/76 westbound. U.S. 220 Business parallels I-99/U.S. 220 north to Cessna. U.S. 220 continues south from the end of I-99 another seven miles to Cumberland Valley. 07/14/24

South End – Past Views

Past Views Gallery (Tap to Expand / Collapse Section)

North at

Replaced by 2005, traffic partitioned into ramps for I-99/U.S. 220 north to State College and U.S. 220 south to Cumberland beyond this set of button copy overheads. 10/08/01

West at

Replaced guide sign on the Pennsylvania Turnpike west for Interstate 99, U.S. 220 and Bedford. 10/15/04