SR 128 begins at the three-way
intersection of San Juan Avenue and Lane Avenue (
SR 103), with SR 128 heading east as a four-lane street with a
center turn lane through
residential and
commercial areas of the Hyde Grove, Hyde Park,
Lake Shore, Fairfax, and
Ortega neighborhoods of Jacksonville. About east of its western terminus at Lane Avenue, SR 128 crosses the Cedar River in the Lake Shore neighborhood and becomes more residential than commercial east of the crossing, heading towards intersections with Cassat Avenue (
SR 111), followed by Blanding Boulevard (
SR 21) just two
blocks to the east. Three blocks east of Blanding Boulevard, San Juan Avenue crosses a double-tracked railway right at the western end of the intersection with
US 17/
SR 15 (
Roosevelt Boulevard), ending the center lane for SR 128 east of the intersection, and passes by the Roosevelt Square Mall at the southeast end of the intersection. It continues for three blocks as a four-lane highway to SR 128's eastern terminus at Herschel Street (
SR 211). San Juan Avenue continues east of Herschel Street under the designation of SR 211 as a two-lane road, heading towards the Ortega Bridge three blocks east of SR 128's eastern terminus. ==Major intersections==