California CodesSHC CodeDivision 1 - STATE HIGHWAYSChapter 2 - The State Highway SystemArticle 3 - The State Highway Routes§ 421§ 421Amended by Stats. 1984, Ch. 409, Sec. 47.Route 121 is from:(a)Route 37 near Sears Point to Route 29 near Napa.(b)Route 29 in Napa to Route 128.Cite this sectionCal. Sts. & High. Code § 421 (2026)Copyhttps://ca.codecond.com/codes/shc/division-1-state-highways/chapter-2-the-state-highway-system/article-3-the-state-highway-routes/section-421CopyOther sections in Article 3 - The State Highway Routes§ 300§ 301§ 301.1§ 301.3§ 301.4§ 301.5§ 302§ 303§ 304§ 305…§ 620§ 621§ 622§ 622.1§ 622.3§ 623§ 624§ 625§ 632§ 635← § 420§ 422 →