The arterial begins at an unorthodox intersection with Swan Street, a one-way, one-lane street that runs along the Empire State Plaza's northwestern edge. Ramps connect the westbound arterial to Swan Street north and Swan Street north to the eastbound arterial, and the arterial itself abruptly ends with a U-turn just west of Swan Street. The highway heads to the southeast, passing under a row of buildings that marks the northwestern boundary of the Empire State Plaza. After a short piece open to the sky, the road heads under the center of the plaza in two tunnels, with access to and from the plaza's parking garage on the right. Two unused tunnels—which would have served through traffic—are present in the center, and two partial tunnels on the outside serve garage traffic.
It emerges from the tunnels just west of Eagle Street, a two-lane road that loosely follows the southeastern boundary of the plaza. The arterial subsequently crosses over Eagle Street, with a westbound ramp providing access to the street and the nearby Times Union Center. Continuing eastward, the eastbound direction of the highway splits into two roads, one leading to the Dunn Memorial Bridge and another connecting to I-787. The two halves of the highway are separated by only a jersey barrier until Pearl Street (US 20 and NY 32), where the arterial enters a large interchange at the western end of the Dunn Memorial Bridge. Although both directions of the arterial are accessible from Pearl Street, there is no eastbound access from the arterial to Pearl Street. The original plans for the highway had included an eastbound exit to the street.
East of Pearl Street, both directions of the highway physically split into two ramps. One roadway in each direction funnels traffic to and from I-787, while the other continues eastward onto the Dunn Memorial Bridge. At this point, the South Mall Arterial gives way to US 9 and US 20, which head across the bridge to Rensselaer. US 9 enters and exits the road via ramps paralleling I-787 to the north of the arterial while US 20 ascends onto the bridge via the Pearl Street entrance and exit ramps. The arterial is inventoried by NYSDOT as NY 913V, an unsigned reference route.