Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
mileage [ˈmaɪlɪdʒ] n (number of miles) пробе́г в ми́лях; (distance) расстоя́ние в ми́лях
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.