A state highway to be known as state route number 409 is established as follows:

Beginning at the South Ferry landing, as now located, or as it may be relocated, on the south side of Puget Island, thence generally northerly by the most feasible route to the Puget Island bridge, thence crossing said bridge to a junction with state route number 4 at the north approach of said bridge at the town of Cathlamet: PROVIDED, That the state of Washington shall not assume or pay any bond or bonds outstanding against said bridge, or interest on said bonds, but said bond or bonds, and interest thereon, shall remain the sole obligation of the obligors named on said bonds.