September 25 is the 268th day of the year (269th in leap years) in the Gregorian calendar. There are 97 days remaining until the end of the year.
1066 – The Battle of Stamford Bridge marks the end of the Viking invasions of England.
1237 – Scotland and England sign the Treaty of York, marking their common border.
1396 – Ottoman Sultan Bayezid I defeats a Christian army at the Battle of Nicopolis.
1493 – From Cadiz, Spain, Christopher Columbus sets sail on his second voyage.
1513 – Spanish explorers become the first Europeans to sight the Pacific Ocean.
1775 – American Revolutionary War: Ethan Allen surrenders to British forces after attempting to capture Montreal during the Battle of Longue-Pointe. Benedict Arnold and his expeditionary company set off from Fort Western, bound for Quebec City.
1789 – The United States Congress passes twelve amendments to the United States Constitution.
1804 – The Teton Sioux demand one of the boats from the Lewis and Clark expedition as a toll for moving further upriver.
1846 – Mexican-American War: US forces under Zachary Taylor capture Monterrey, Mexico.
1868 – The Imperial Russian steam frigate Alexander Neuski is shipwrecked off Jutland while carrying Grand Duke Alexei Alexandrovich of Russia.
1890 – Sequoia National Park in California is founded.