WHAT ALL HAPPENED APRIL TO SEPTEMBER 1846
Find out what all happened April to September 1846

Elias Howe is granted a patent for the sewing machine. (10. September 1846)

Mexican–American War: The United States declares war on Mexico. (13. May 1846)

The Oregon Treaty establishes the 49th parallel as the border between the United States and Canada, from the Rocky Mountains to the Strait of Juan de Fuca. (15. June 1846)

Thornton Affair: Open conflict begins over the disputed border of Texas, triggering the Mexican–American War. (25. April 1846)

The few remaining Mormons left in Nauvoo, Illinois, formally dedicate the Nauvoo Temple. (1. May 1846)

The Smithsonian Institution is chartered by the United States Congress after James Smithson donates $500,000. (10. August 1846)

U.S. forces led by Zachary Taylor capture the Mexican city of Monterrey. (25. September 1846)

President James K. Polk asked for and received a Declaration of War against Mexico, starting the Mexican–American War (11. May 1846)

Mexican–American War: American troops occupy Monterey and Yerba Buena, thus beginning the U.S. acquisition of California. (7. July 1846)

Elizabeth Barrett elopes with Robert Browning. (12. September 1846)

The Cambridge Chronicle, America's oldest surviving weekly newspaper, is published for the first time in Cambridge, Massachusetts (7. May 1846)

Two French shepherd children, Mélanie Calvat and Maximin Giraud, experience a Marian apparition on a mountaintop near La Salette, France, now known as Our Lady of La Salette. (19. September 1846)

Mexican–American War: General Zachary Taylor captures Monterrey. (24. May 1846)

Mexican–American War: The Battle of Palo Alto – Zachary Taylor defeats a Mexican force north of the Rio Grande in the first major battle of the war. (8. May 1846)

Astronomers Urbain Jean Joseph Le Verrier, John Couch Adams and Johann Gottfried Galle collaborate on the discovery of Neptune. (23. September 1846)

Mexican–American War: President Mariano Paredes of Mexico unofficially declares war on the United States. (23. May 1846)

The Papal conclave of 1846 concludes. Pope Pius IX is elected Pope beginning the longest reign in the history of the papacy. (16. June 1846)

Bear Flag Revolt begins – Anglo settlers in Sonoma, California, start a rebellion against Mexico and proclaim the California Republic. (14. June 1846)

The saxophone is patented by Adolphe Sax in Paris, France. (24. June 1846)

The Donner Party of pioneers departs Springfield, Illinois, for California, on what will become a year-long journey of hardship, cannibalism, and survival. (14. April 1846)