The state highway runs 5.18 miles (8.34 km) from SR 10 in Chesterfield east to U.S. Route 1 and US 301 in Bellwood in eastern Chesterfield County.

The state highway heads east as two-lane undivided Centralia Road toward the hamlet of Centralia, where the highway has a grade crossing of CSX's North End Subdivision.

North of the freeway, SR 145 closely parallels CSX's Bellwood Subdivision rail line northeast to Bellwood.

There, the highway veers east and makes a 90-degree turn north at Perrymont Road.

SR 145 veers east again and reaches its northern terminus at US 1 and US 301 (Jefferson Davis Highway).