The route then passes through Prince William crossing Joslin Creek Basin then entering Lower Prince William as it passes Kings Landing and an interchange with Route 635.

The route continues past Longs Creek Passing the northern terminus Of The New Brunswick Route 3 Continuing Following the river past Woolastook Park and the Mactaquac Dam through Upper Kingsclear, Central Kingsclear, and Lower Kingsclear, as well as French Village and Island View as it enters Fredericton.

The route enters Fredericton in the neighbourhood of Silverwood continuing onto the Woodstock Road, then follows Brunswick Street or a riverfront parkway known as St. Anne's Point Drive (depending on direction) through the downtown area, leaving on Waterloo Row.

Route 102 continues to follow the river along Lincoln Road, passing the Fredericton International Airport and reaching the town of Oromocto.

With the alignment of the Trans-Canada Highway bypassing Saint John, and the upgrades of the Broad Road in the 1950s taking most traffic off the River Road, its importance as a major traffic route diminished.