Final answer:
The U.S. government's major accomplishment under the Articles of Confederation was establishing a system for the formation of new states through land ordinances.
Step-by-step explanation:
One major accomplishment of the U.S. government under the Articles of Confederation was creating a system for forming new states.
This was achieved through the enactment of land ordinances, which outlined how the government would manage the addition of new states to the union.
While the Articles had numerous weaknesses, including the inability to tax and raise a national military effectively, they provided a framework for western expansion and statehood which later influenced the Northwest Ordinance under the new Constitution.