ˌɔn mˈɑːɹtʃ wˈʌn, nˈaɪntiːnhˈʌndɹɪd twˈɛnti wˈʌn, ɹˈaʊt fˈoːɹbˈiː wʌz ɹᵻnˈʌmbɚd tə ɹˈaʊt fˈoːɹɾi sˈɪks ænd ɛkstˈɛndᵻd wˈɛstwɚd ɐlˈɔŋ wʌt ɪz nˈaʊ ˌɛnwˈaɪ tˈuːhˈʌndɹɪd fˈoːɹɾi ˈeɪt ænd ˌɛnwˈaɪ nˈaɪntiːn tə wˈɛlzvɪl.
On March 1, 1921, Route 4-b was renumbered to Route 46 and extended westward along what is now NY 248 and NY 19 to Wellsville.