What important purchase occurred in 1803, impacting the territory of New Orleans?

The significant event that took place in 1803, profoundly affecting the territory of New Orleans, was the Louisiana Purchase. This landmark acquisition involved the United States purchasing approximately 828,000 square miles of territory from France. The inclusion of New Orleans in this purchase was pivotal because it provided the U.S. with control over the Mississippi River and access to vital trade routes, bolstering its economic and strategic interests.

The Louisiana Purchase also doubled the size of the United States, catalyzing westward expansion and manifest destiny. The strategic location of New Orleans as a port city made it crucial for the transportation of goods, and the transfer of power from French to American governance significantly shaped the development of the region's culture, economy, and demographics.

In contrast, the other options refer to different historical transactions or events that occurred in other contexts and time periods, unrelated to the acquisition of New Orleans specifically. The Gadsden Purchase and the Florida Purchase came later in the 19th century, and the Texas Annexation was a separate political process often linked to the expansionist policies that followed the Louisiana Purchase, but did not directly involve New Orleans at that time.