North America's most prominent river system in terms of the area of its drainage basin is the Missouri Mississippi.
Step-by-step explanation:
The Missouri River is the river that is longest in nature. This lies in the North America. It is about 2,341 miles in length. It rises in the western Montana and continues to flow from east and south for about 3,767 km. This river drains a semi-arid watershed that is of more than 500,000 square miles and is a sparsely populated area.
It carries a volume of water that is more comparably and it is the 4th longest river in the world. It drains about 10 states in U.S and two number of provinces in Canada. Thus, the Missouri Mississippi is the most prominent river system in North America in terms of the ares that is drains.