The highway begins midway across the Columbia River on the National Register of Historic Places listed Lewis and Clark Bridge and travels north to SR 432 in Longview.

SR 433 enters Washington and Cowlitz county on the National Register of Historic Places listed Lewis and Clark Bridge over the Columbia River.

The highway continues north, paralleling railroad tracks belonging to the Columbia and Cowlitz Railway,[2] intersecting Port Way again, and gaining one lane in each direction for a total of four lanes before the highway terminates at an intersection with SR 432 and Industrial Way.

[3] The highway has a posted speed limit of 35 miles per hour (56 km/h) for its entire length.

[6] SR 433 and the Lewis and Clark Bridge form part of the Seattle to Portland Bicycle Classic, serving as the link between Washington and Oregon on the 202 mi (325 km) long bicycle race held annually.