Analysis of information sources in references of the Wikipedia article "Washington State Route 503" in English language version.
State Road No. 15, or the Lewis River road, beginning at Woodland in Cowlitz County and running thence up the north bank of Lewis river, following as nearly as practicable the county road, and continuing to the mouth of the Big Muddy, a tributary of Lewis river in Skamania county.
State Road No. 10; Section 5901-j, Rem. & Bal. Code, establishing State Road No. 19; Section 5903, Rem. & Bal. Code, establishing State Roads Nos. 14, 15, 16 and 17, and that paragraph of Section 5905, Rem. & Bal. Code establishing State Road No. 7 and extensions, be and the same are hereby repealed.
(r) Secondary State Highway No. 1S; beginning at a junction with Primary State Highway No. 1 in the vicinity north of Woodland, thence in an easterly direction by the most feasible route to Amboy, thence in a southerly direction by the most feasible route to Battleground, thence in a westerly direction by the most feasible route to a junction with Primary State Highway No. 1 in the vicinity north of Vancouver; (t) Secondary State Highway No. 1U; beginning at Battleground on Secondary State Highway No. 1S, thence in a southerly direction by the most feasible route to Orchard on the Secondary State Highway No. 8A.