ɪɾ ɪnˈɪʃəli kˈʌvɚd ðɪ ˈiːstɚn hˈæf ʌvðə lˈoʊɚ pənˈɪnsjʊlə, aʊtsˈaɪd ðə sˈaʊθiːst mˈɛtɹoʊ dɪtɹˈɔɪt ænd flˈɪnt, wˌɪtʃ wʌz ɐsˈaɪnd ˈɛɹiə kˈoʊd θɹˈiːhˈʌndɹɪd θˈɜːtiːn.
It initially covered the eastern half of the Lower Peninsula, outside the southeast (Metro Detroit and Flint), which was assigned area code 313.