θɹuːˈaʊt ðə wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd z, ðə juːnˈaɪɾᵻd stˈeɪts, wˈɑːʃɪŋtən tˈɛɹɪtˌoːɹi, ænd pɹˈaɪvət pˈɑːɹɾiz ɛksplˈoːɹd ðə kənstɹˈʌkʃən əvə wˈæɡən ɹˈoʊd ɔːɹ ɹˈeɪlɹoʊd ˌoʊvɚ ðə pˈæs, bˌʌt nˌɪɹli ˈɔːl sˈʌtʃ ɐtˈɛmpts fˈeɪld.
Throughout the 1800s, the United States, Washington Territory, and private parties explored the construction of a wagon road or railroad over the pass, but nearly all such attempts failed.