Today is an exact date in U.S. military history, although specifics of that history can be difficult to track down.
The National Museum of the U.S. Army calendar says it's the start of the Black Hawk War.  The Veterans of Foreign Wars calendar has no entry. The Army Almanac has no write up about it, but in the chronology states, “April 26 to 30 September (1832) Black Hawk Campaign.”
The Army official history book, "American Military History," has a brief write-up about it, but calls it neither a war nor a campaign. You’ll have to figure out for yourself what it was.
Black Hawk was the chief of a band of Sac Indians that had fought for the British in the War of 1812. A treaty ceded former Sac lands to the rapidly encroaching Americans who were heading West in droves.
Chief Black Hawk disregarded the treaty, and with some 500 warriors and 1,500 women and children, moved back into the disputed land in western Illinois and claimed it. Not so fast, said the U.S. Army leaders in the area.  
Col. Henry Atkinson was dispatched from Jefferson Barracks near St. Louis to drive the Sac from the land. The always reliable Chronicle of America, a huge 951-page tome given to me by a reader many years ago to “help with my research” had a write up about the only pitched battle of the war, or campaign.
“In the wake of last month’s crushing defeat of Chief Black Hawk at the battle — some call it massacre — of Bad Axe, the rival Sauk chief, Keokuk, has signed an agreement giving up his tribe’s claims to lands east of the Mississippi. In doing so, he confirms an earlier treaty that was negotiated by Gen. William Henry Harrison, but was later rejected by Black Hawk as a fraud on his people.”
The fighting, or skirmishes, had lasted two years but were doomed to failure from the Indians’ standpoint. Even the U.S. warship Warrior sailed up river systems to assist in the fighting, making it a joint Army and Navy enterprise.
Perhaps one of the most notable happenings in the conflict was not mentioned in any of the references sited. But, in earlier readings about the brief conflict I learned that when the call for volunteers went out in Illinois, an unknown young budding lawyer signed up.
In those days, troops in militia units elected the officers, and Pvt. Abraham Lincoln was quickly elected captain of his company. I found no evidence that he participated in any action and thus was not wounded, but he did serve as an officer in an Illinois militia unit.
Another little known fact was learned at a local flea market several years ago. I’d picked up metal objects called grave markers for several years.
When veterans died, family members could purchase metal markers, usually on a pole about two feet long, and drive the marker into the ground at the grave site.
The marker indicated for all who visited that the deceased soldier had served in a war. Markers began after the Revolutionary War, as I also have one from that first conflict.
I haven’t found one yet from the War of 1812, but have one from other wars up to Korea.
Yes, I even have a grave marker that proclaims “Black Hawk War.”  So that, plus the aforementioned calendar, may trump the entry of the Black Hawk Campaign.
OK, maybe not.
But, the little known footnote in U.S. military history began 182 years ago today.  One of these days, I just might have to delve deeper into the events of that little footnote.