A Strategic Point is a predetermined place on the map where towers can build. When not restricted (in the Iron Challenges), any tower can be built on an available point, and it is the goal of the game to make best use of the available towers to effectively kill enemies and stop them reaching the goal.
In Kingdom Rush: Frontiers, a new mechanic was added to the strategic points, a means to limit the number available in any one level. Beginning with Crimson Valley and throughout the rest of the jungle levels, some strategic points are covered in Overgrowth preventing anything from being built there. The overgrowth can be removed at a cost of 100 gold, freeing the point up. From The Underpass and the following underground levels, some points are covered in Rubble and will require 200 gold to clear.