Which of the following events contributed the largest blocks of land to the United States?

The Louisiana Purchase significantly expanded the territory of the United States by acquiring approximately 828,000 square miles of land from France in 1803. This monumental land deal nearly doubled the size of the nation at the time, allowing for westward expansion and the exploration of new territories.

The Annexation of Texas in 1845 added another important piece of land, as Texas was an independent republic before joining the U.S., contributing approximately 389,000 square miles. This event played a crucial role in the U.S. expansionist ideology known as Manifest Destiny.

Following the Mexican-American War, the Mexican Cession in 1848 ceded vast territories to the U.S., including present-day California, Nevada, Utah, Arizona, and parts of Colorado and New Mexico. This added around 500,000 square miles of land to the country.

Considering the significance and magnitude of the land acquired through the Louisiana Purchase, the Annexation of Texas, and the Mexican Cession, it is accurate to say that all of these events contributed the largest blocks of land to the United States. Each event was pivotal in shaping the territorial boundaries of the nation, reinforcing the idea that nation's land expansion was a vital component of its growth and development.