Why did Prussia dominate the North German Confederation?

Prussia dominated the North German Confederation primarily due to its decisive military victory over Austria in the Seven Weeks’ War in 1866, which established Prussia as the sole dominant power in Germany.12

Following this victory, Prussia overshadowed the other member states so significantly that its will was almost certain to prevail in any political or administrative matter. This hegemony was codified in the confederation's structure:2
* Leadership: The king of Prussia served as the president of the confederation, and the Prussian chancellor held the same role for the union.1
* Constitutional Control: Prussia held 17 of the 43 seats in the Bundesrat, granting it the power to veto any constitutional changes.2
* Centralized Authority: The federal government, directed by Prussia, maintained control over critical areas including foreign affairs, the military, and economic policy.2

By creating this union, Otto von Bismarck effectively unified the states north of the Main River under Prussian leadership, using the confederation as a foundational step toward broader German unification.12