Climatic and relief factors could limit the distribution of nonmigratory animals, and especially those that inhabit temperate areas. The limitations are stronger for habitat specialist species and a good understanding of these influences can contribute significantly to the development of conservation measures to protect them. The European ground squirrel (Spermophilus citellus) is a small mammal inhabiting pastures and areas of short herbaceous vegetation from Central and Southeastern Europe with limited data about their colony site selectivity. During the first wide survey of the European ground squirrel in Eastern Romania we identified a strong influence of annual precipitation, aspect, slope, vegetation height, and tree/bush coverage on the species' distribution and density. Lower precipitation values were associated with higher densities of European ground squirrel as well as slope. The same relationship was found with vegetation height and the amount of tree and bush coverage. The European ground squirrel uses areas with a southern and eastern aspect and slopes with a higher gradient. The elevation and the summer-winter temperatures do not have a significant influence on European ground squirrel colonies. Our results will contribute to the species' conservation across its distribution range and will help to determine the most appropriate sites for future relocation and repopulation programs.