It extended for just under 18 miles (29 km) from an intersection with NY 27 near the Holland Tunnel in Lower Manhattan to an interchange with U.S. Route 1 (US 1) just north of the New York City line in the Westchester County village of Pelham Manor.

In Manhattan and the South Bronx, NY 1A used several surface streets to traverse the boroughs, including a handful of one-way roads.

It initially headed north on a one-way couplet, with northbound NY 1A following Sixth Avenue and southbound traffic using Varick Street one block to the west.

The highway continued to follow Houston Street until a junction with Second Avenue, the south end of another one-way couplet.

[1] Earlier plans, drawn up in 1932 and 1933 by the New York Automobile Club, took US 1 through the Holland Tunnel and north through the upper east side of Manhattan.

[6] The new highway became part of NY 1A, which was rerouted through the Bronx to follow Bruckner Boulevard and Shore Road to Pelham Bay Park.

[7][8][9] A second southward extension of the parkway from Pelham Bay Park to NY 1A at the Bruckner Interchange opened in 1941.