 I-180 and US 220 run together northeast/southwest through Williamsport, and US 15 joins (in the opposite direction) for two miles.Once completed, Interstate 99 will enter Williamsport from the southwest on US 220 and continue north on US 15, joining only one at a time.There is no passenger rail service, but, until the mid-20th century, Williamsport was a major transfer point between the Pennsylvania Railroad (PRR), Reading Railroad, and New York Central Railroad.