March 10 is the 70th day of the year. There are 296 days remaining until the end of the year.
- 1804 – In St. Louis, Missouri, a formal ceremony to transfer ownership of the Louisiana Territory from France to the United States.
- 1831 – The French Foreign Legion was established by King Louis-Philppe to support his war in Algeria.
- 1848 – The Treaty of Guadalupe Hidalgo was ratified by the United States Senate, ending the Mexican-American War.
- 1876 – Alexander Graham Bell made the first successful telephone call saying, "Mr. Watson, come here, I want to see you."
- 1891 – Almon Strowger, an undertaker in Topeka, Kansas, patented the Strowger switch, a device that led to the automation of telephone circuit switching.
- 1906 – Europe’s worst mine disaster, in Courrières, France, killed 1099 miners.
- 1922 – Mahatma Gandhi was arrested in India, tried for sedition, and sentenced to six years in prison. He was released after two years for an appendectomy.
- 1959 – Fearing an abduction attempt by China, 300,000 Tibetans surrounded the Dalai Lama’s palace to prevent his removal.
- 1977 – Astronomers discovered rings around Uranus.