SR 306 was first designated in 1932 following its current route between US 322 and SR 283. In 1935, the Aurora-US 422 segment was brought into the state highway system, but as SR 382.
SR 306 was first established in 1932 along its current route between US 322 and SR 283, and in 1935, the Aurora-US 422 segment became part of the state highway system under designation as SR 382.