Following its intersection with Eckstein Road (TR 166), SR 181 crosses over the US 30 freeway, and arrives at its endpoint at SR 309, a T-intersection located just  west of the Ontario city limit.
SR 181 meets Eckstein Road (TR 166), then crosses over the US 30 highway, and finally reaches its endpoint at SR 309, a T-intersection situated just outside the Ontario city limits.