Interstate 99 is a disjointed highway with one segment in central Pennsylvania and the other in southern New York. The southern terminus is at the Pennsylvania Turnpike north of Bedford in Pennsylvania. Travelling north, I-99 ends at I-80 near Bellefonte.
The New York segment begins at the Pennsylvania border and travels north to an interchange with Interstate 86 in Corning.
The entire interstate is concurrent with US Highway 220 and has a total distance of 98.86 miles. Unlike other interstate highways, whose numbers are assigned by the AASHTO, Interstate 99’s number was assigned by a congressional act, and as a result violates typical numbering conventions as it’s east of Interstate 79 and west of Interstate 81.