When looking for the Axe from the Lake using the map and journal in Kingdom Come Deliverance 2, you'll notice a large area is highlighted around Rocktower Pond in the west of the Trosky region. The axe is buried in a grave found on top of the hill roughly north of the Rockwater Pond pier within this highlighted area.

While it'll take a long, long time to finish the main story of Kingdom Come: Deliverance 2, the countless side quests in the game are some of the most interesting moments. At times, they'll take hours to finish and you'll meet some really unique characters you'd otherwise never know existed.