hi! not discouraging more nominations, but FYI, this sort of question has come up before, so catch some previous responses here

What is the earliest reliable documented event in human history?

What is the earliest recorded date that we can determine accurately?

otherwise, you might try x-posting to /r/AskAnthropology, as they may have more info on dating events from prehistory, or /r/AskScience regarding precisely-calculable natural events like solar eclipses

I want to add one example to the list of examples in the other two topics. For North America there is a section of a book titled Skull Wars by David Hurst Thomas. He talks about a 7,400 year old oral story that survived to the 1800s when an American soldier wrote it down. I'll lift the passage which starts on page 249.

Chief Lalek begins the Klamath story like this: "A long time ago, so long that you cannot count it the white man ran wild in the woods and my people lived in rock-built houses. In that time, long ago, before the stars fell, the spirits of the earth and the sky, the spirits of the sea and the mountains, often came and talked with my people..." Lalek then described the spirits living inside Mount Mazama and its sister mountain, Mount Shasta. The two massive peaks had openings that led to a lower world through which the spirits could pass. The Chief of the Below-World loved a Klamath chief's daughter, Loha, and demanded that she marry him. When this amorous overture was rebuked, the result did not sit well with the spirit, who threatened total destruction of the people as revenge. "Raging and thundering," the story went, "he rushed up through the opening and stood on top of his mountain," terrorizing the people below.

At this point, the spirit of Mount Shasta intervened as a cloud appeared over the peak of Shasta, and the two mountains engaged in a horrible combat: "Red-hot rocks as large as hills hurled through the skies. Burning ashes fell like rain. The chief of the Below-World (Mazama) spewed fire from its mouth. Like an ocean of flame it devoured the forests on the mountains and in the valleys. On and on the Curse of Fire swept until it reached the homes of the people. Fleeing in terror before it, the people found refuge in the waters of Klamath Lake."

The Klamaths then decided that someone should be sacrificed to calm the chaos. Two medicine men climbed Mount Mazama and jumped into the caldera: "Once more the mountains shook. This time the Chief of the Below-World was driven into his home and the top of the mountain fell upon him. When the morning sun arose, the high mountain was gone... for many years, rain fell in torrents and filled the great hole that was made when the mountain fell..."

Chief Lalek ended his story this way: "Now you understand why my people never visit the lake. Down through the ages we have this story. From father to son has come the warning, "look not upon the place... for it means death or everlasting sorrow."

Deloria emphasizes the parallels between the pre-1865 Klamath account-recorded decades before the first scientist explored Crater Lake-and the modern geological explanation, which dates only to the 1920s. In both, Mount Mazama was destroyed in a catastrophic explosion, characterized by superheated avalanches, a massive cloud of volcanic dust, the dramatic collapse of the peak into the belly of the mountain, and the formation of a new deepwater lake atop the truncated mountain.

In order to flesh out a lot of the short and somewhat confused posts in the other two threads, a few comments on the sources for Mesopotamian, Syrian, and Anatolian chronology might be apposite here. We can divide these sources into two kinds: sources on relative chronology and sources on absolute chronology.By relative chronology is meant the succession and spacing of events. This is relatively abundantly attested from a variety of sources going back to the third millennium BCE-king lists, royal inscriptions, economic texts which are dated by year name or epynomy (that is, name of an Assyrian official who changes annually), but there are some important gaps and places where our records are fragmented from the mid-second millennium on back. We'll get back to that later. By absolute chronology is meant the precise timing of events(that is, X year B.C.E. on Y date). This is rather trickier because years were generally kept by year-name(that is, "year in which ____ event happened"), regnal year, or officeholder in Assyria rather than a astronomical year calendar comparable to the Mayan Long Count.

The problem with Mesopotamian chronology then is how you manage to attach absolute dates to our known relative chronology. Parts of this are relatively easy; we can use the somewhat better preserved Egyptian astronomical records, check that against Babylonian astronomical diaries and Assyrian records, and use the astronomically verifiable dates to work backwards from there. This allows us to give very exact dates for the first millennium, because the Assyrian records are very well-preserved and we can work backward from our usable synchronisms for a fair chunk of the first millennium. For the second millennium, it is trickier because there are several quite important places where our records are patchy or discontinuous, or otherwise difficult to synchronize with each other. We can use Hittite-Egyptian synchronisms(this is why the Battle of Kadesh is often cited as our "earliest datable event; it's a useful Egyptian-Hittite synchronism). We can also refer to a solar eclipse mentioned by the Hittite Mursili II in the tenth year of his reign, although there are multiple possible candidates for this eclipse. This is probably the oldest event to which I would feel comfortable speaking of it being a realistic possibility to establish an exact year, although that is very iffy. Going further back into the past, we continue to have a mostly working relative chronology based on year names and king lists for the mid-and-early 2nd millennium but absolute chronology remains uncertain because our astronomical data admits of several possible dates for a crucial event and it's harder to produce Egyptian synchronisms. We do have a semi-functional relative chronology going back into the third millennium, although it becomes patchier and more based on estimates(admittedly estimates on the order of 50 years rather than 200) the further back you go. But a lot of ancient history is founded on careful estimates and not on having exact numbers.

A note on radio-carbon dating: Radiocarbon dating and other istotopic dating methods are very important for a lot of things; dating archaeological strata, paleoclimate studies, and in many cases giving us solid foundations on which to lay estimates about how the relative chronology falls in absolute terms. However, it is difficult to found an exact chronology on it both because inevitably there's some uncertainty in all radiocarbon dates(although modern dating techniques are getting more and more precise) and because it's tricky to link radiocarbon samples to specific historical events or documents.