nˈʌn ʌv ɹˈaʊt fˈɪftiːn bᵻtwˌiːn mˈʌmfɚd ænd skˈɑːtzvɪl wʌz ɐsˈaɪnd ɐ dˌɛzɪɡnˈeɪʃən wɛn ðə fˈɜːst sˈɛt ʌv ɹˈaʊts ɪnðə mˈɑːdɚn stˈeɪt hˈaɪweɪ sˈɪstəm wɜːɹ ɐsˈaɪnd ɪn nˈaɪntiːnhˈʌndɹɪd twˈɛnti fˈoːɹ.
None of Route 15 between Mumford and Scottsville was assigned a designation when the first set of routes in the modern state highway system were assigned in 1924.