Answer:

USONE

AnswerCrossword Clue
USONELongest north-south highway in America
USONEEast Coast rte.
USONERte. that parallels I-95
USONERoad from Fort Kent, Maine, to Key West, Fla.
USONEIt passes through six E. state capitals
USONEMuch of the Boston Post Rd., now
USONEIts mile zero is in Key West, Fla.
USONERte. through six Eastern state capitals
USONEMe.-to-Fla. highway
USONEIt parallels I-95
USONEHwy. paralleling I-95
USONEMe.-to-Fla. route
USONEMaine-to-Fla. highway
USONEHighway to Fla.
USONEAuto route from Me. to Fla.
USONERoute from Me. to Fla.
USONEEastern seaboard rte.
USONEIt joins I-10 in Jacksonville and I-90 in Boston
USONEIn Key West it's known as the Overseas Hwy.
USONEMaine-to-Florida rte.
USONERte. with a terminus in Key West, Fla.
USONERte. from Maine to Florida
USONELongest American north-south rte.