SR 145 begins at an intersection with SR 10 in Chesterfield. 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. Just east of the railroad crossing, SR 145 meets the northern end of SR 144. SR 145 turns north onto Chester Road, which is a four-lane divided highway from just south of the SR 144-SR 145 intersection to north of the state highway's diamond interchange with the SR 288 freeway. North of the freeway, SR 145 closely parallels CSX's Bellwood Subdivisionrail linenortheast 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.