The original SH 91 was designated on October 15, 1923 on a similar route from Denison north to a different Red River crossing west of the current one, where it connected with Oklahoma Highway 48 (now OK-70A).
ðɪ ɚɹˈɪdʒɪnəl ˌɛsˈeɪtʃ nˈaɪnti wˈʌn wʌz dˈɛzɪɡnˌeɪɾᵻd ˌɔn ɑːktˈoʊbɚ fˈɪftiːn, nˈaɪntiːnhˈʌndɹɪd twˈɛnti θɹˈiː ˌɔn ɐ sˈɪmɪlɚ ɹˈaʊt fɹʌm dˈɛnɪsən nˈɔːɹθ tʊ ɐ dˈɪfɹənt ɹˈɛd ɹˈɪvɚ kɹˈɔsɪŋ wˈɛst ʌvðə kˈɜːɹənt wˌʌn, wˌɛɹ ɪt kənˈɛktᵻd wɪð ˌoʊklɐhˈoʊmə hˈaɪweɪ fˈoːɹɾi ˈeɪt nˈaʊ ˌoʊkˈeɪ sˈɛvənti ˈeɪ.