Although he was born in Borlänge, Mikael Blomkvist spent little time there as a child. His family moved to Lilla Essingen (Smaller Essingen) - one of Stockholm's 14 islands - when he was very young.
Blomkvist's primary school was located on Lilla Essingen.
Click on the image for a better view.
Image of Lilla Essingen (Smaller Essingen), online courtesy Wikimedia Commons.