The map found in the player's home above the telephone table shows the area surrounding lake Peräjärvi (lit. end/bottom/rear lake) in the (fictional) municipality of Alivieska. The map covers an area of about 4.2 × 3.3 kilometres. The map is from 1989 so it's at least six years old in game.
On the map red lines are paved roads while dark red lines are unpaved roads (dirt roads). Yellow areas are farm fields and the large brownish area to the east of the lake is marsh. Gray areas are gravel pits. Blank white areas are generally inaccessible forested areas.