For the Russians , in what city does "Santa Claus" live?

Hi Mozart,
Russians know Santa Claus as Grandfather Frost.
According to tradition, Grandfather Frost and Snegurochka, a young girl, live in the town Veliky Ustug from which they begin their New Year journey by troika of white horses.

Today Grandfather Frost is connected to New Year celebrations, but before 1917 he was much more related to Christmas. Grandfather Frost and Snegurochka visit children asking them to sing or read a poem, sometimes asking if they were good, and of course giving presents.

Apparently Snegurochka is his granddaughter...at least that's what he's telling all the boys and girls.

Christmas Connection

Right on dance girl. You've hit my source.