1803    In New Orleans, Louisiana, Spanish representatives officially transfer the Louisiana Territory to a French representative. Just 20 days later, France transfers the same land to the United States as the Louisiana Purchase.

1811    The first steamboat to sail the Mississippi River arrives in New Orléans, Louisiana.

1830    The Great fire of New Orleans, Louisiana begins.

1855    Texas is linked by telegraph to the rest of the United States, with the completion of a connection between New Orleans and Marshall, Texas.

1862    American Civil War: A flotilla commanded by Union Admiral David Farragut passes two Confederate forts on the Mississippi River on its way to capture New Orleans, Louisiana.

1862    American Civil War: Forces under Union Admiral David Farragut capture the Confederate city of New Orleans, Louisiana.

1862    American Civil War: New Orleans, Louisiana falls to Union forces under Admiral David Farragut.

1868    The first parade to have floats is staged at Mardi Gras in New Orleans, Louisiana.

1965    Hurricane Betsy makes its second landfall near New Orleans, Louisiana, leaving 76 dead and $1.42 billion ($10–12 billion in 2005 dollars) in damages, becoming the first hurricane to top $1 billion in unadjusted damages.

1973    Mark Essex fatally shoots 10 people and wounds 13 others at Howard Johnson's Hotel in New Orleans, Louisiana before being shot to death by police officers.

2005    Hurricane Katrina begins to make landfall in Louisiana and Mississippi in the afternoon, and brings the most severe damage to Slidell and New Orleans.