We review the long-standing (1958-2014) materials on the extending, number, reproduction, spatial and environmental structure of the grey red-backed vole (Myodes rufocanus Sund., 1846) population of the Eastern Fennoscandia, that represents the south-west area periphery. It was found that the species is spread in the northern part of the region only, and it is characterized by tiling and unsustainable and low population. The average long-term population of the species for the entire territory of Karelia was 0.005 specimens per 100 trap-days (0.04% of the total catch of small mammals) and 0.005 per 10 specimens of the groove-days (0.04 %), and for the Northern half of this territory — 0.08 specimens per 100 trap-days (1.9%). The overwintered females produce two or three litters and the new adult female voles bear up to two for a season of reproduction. The population comprises several seasonal generations of the young, differing in the rates of growth and development, and the scope of participation in breeding. Juveniles from early litters of the year are known for the rapid growth and development, and almost all of them breed in the year of birth. The young born in the second half of July or later mainly mature only after a winter. Litter size is from 2-3 up to 11-13 with an average of 6.5 fetal for a female, which is obviously lower than the values in the optimum area. The intensity and timing of breeding vary among years depending on the environmental conditions and the consolidated population abundances.