ðə kˈaʊnti bˈoːɹdɚ ɹˈʌnz θɹuː ðə nˈɔːɹθwˈɛstɚn pˈɑːɹt ʌvðə lˈeɪk, ænd ðˈɛn tˈɜːnz ˈiːstwɚdz, wɪððə wˈɛstɚn ænd sˈʌðɚn pˈɑːɹts ʌvðə lˈeɪk bˌiːɪŋ ɪn lˈɔŋfɚd ænd ðə nˈɔːɹθˈiːstɚn pˈɑːɹts bˌiːɪŋ ɪn kˈævæn.
The county border runs through the north-western part of the lake, and then turns eastwards, with the western and southern parts of the lake being in Longford and the north-eastern parts being in Cavan.