The highway then shifts into an east-west alignment and has an intersection with the western terminus of the Foothills Parkway before passing by Chilhowee Dam and going through the Tallassee community.

The two routes proceed northeast as a five-lane undivided highway with a center turn lane to enter the city of Maryville.

Passing initially through mostly residential areas, the highways have an intersection with the southern terminus of SR 335 (William Blount Drive).

The highway then has an at-grade railroad crossing before coming to a directional-T interchange with SR 35 (N Hall Road), which also provides access to downtown Maryville.

Immediately within the city limits of Knoxville, the route has an interchange with SR 168 (Governor John Sevier Highway) a short distance later east of the Fort Loudoun Lake impoundment of the Tennessee River.

Immediately on the other side of the river, the highway has interchanges with US 11/US 70/SR 158 (Neyland Drive) and Kingston Pike, and runs along the western edge of The University of Tennessee.

US 129 then crosses a series of railroads and surface streets on a long viaduct through industrial areas before coming reaching its northern terminus at an interchange with I-40.

[2] The Alcoa Highway portion of US 129 was first constructed and completed as a two-lane roadway from Knoxville to Blount County in 1939 to provide access to the then recently opened McGhee Tyson Airport.

On November 29, 1963, the final project to widen Alcoa Highway into a four-lane median-divided facility between I-40 and McGhee Tyson Airport was completed and dedicated by Tennessee Governor Frank G. Clement, U.S.

Major planning by the Tennessee Department of Transportation (TDOT) in the 1980s and 1990s recommended median crossing closures, new overpass structures, and the widening into a six-lane facility.

Around the same time, the City of Knoxville installed lighting along the highway from the Little River north to the UTMC following annexation of the US 129 right-of-way and selected neighboring commercial and residential land-uses.

[6] This section would be mostly complete by the fall of 2021, when new revisions for an access roadway to the Montlake Drive interchange were issued, expecting to be finished in the winter 2022.

[7] The next phase that will construct the Alcoa Highway between Woodson Drive to Cherokee Trail was started in July 2023 and is expected to be completed by Fall 2027.