United States anniversaries
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- 1846 – In what becomes known as the Thornton Affair, open conflict begins over the disputed border of Texas, triggering the Mexican–American War.
- 1898 – The United States congress officially declares war on Spain. Combat in the Spanish–American War, however, had begun four days prior.
- 1938 – U.S. Supreme Court delivers opinion in Erie Railroad Co. v. Tompkins that overturns a century of federal common law.
- 1944 – The United Negro College Fund is incorporated.
- 1953 – Francis Crick and James D. Watson publish Molecular structure of nucleic acids: a structure for deoxyribose nucleic acid describing the double helix structure of DNA (pictured).
- 1959 – The St. Lawrence Seaway, linking the North American Great Lakes and the Atlantic Ocean, officially opens to shipping.
Usage
These United States "Anniversaries for <date>" (e.g., April 25) subpages are displayed using {{CURRENTMONTHNAME}} {{CURRENTDAY}}.
- The layout design for these subpages is at Portal:United States/Anniversaries/Layout.
- Add a new anniversary to the applicable day of the month shown below.
United States anniversaries by month
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Single page version (long)
Nominations
Feel free to add undisplayed United States-related anniversaries from these resources.
- Daily U.S. portal "Anniversaries" pages, such as Portal:United States/Anniversaries/April/April 25.
- Daily U.S. portal "On this day" pages, such as Portal:United States/On this day/April 25.
- Yearly "...in the United States" articles, such as 2024 in the United States.
- Day of the month articles, such as April 25.
- Month of the year articles, such as April 2024.
- Year articles, such as 2024.
United States-related anniversaries should be included in at least one of the calendar-based articles listed above before they are included here. Possible sources for developing additional calendar-based anniversary items are listed below.