Below is a comprehensive timeline of Faulkner's stories set in Yoknapatawpha county. I included the John Sartoris WWI stories, but left out A Fable, which has a brief, non-important appearance of a Beauchamp. I also included "Old Man" since it was so close to home.
Most of the stories can be dated to within a couple of years using internal evidence or reference to events in the actual world. If I had nothing more to go on than the publication date, I include that in the notes. If a story ranges over a long time span or if it has a narrative frame, I have placed it in the list at its latest date, and put the date range in the notes. So, for example, I have put Absalom, Absalom! in 1909, since that is the 'present day' of the story, and then list 1830-1874 in the notes. When several stories happen in the same year, I have not tried to order them within the year unless they are related to each other. Since Snopes (The Hamlet, The Town, and The Mansion) is more of a loose chronicle than his other works, I have broken it down into more or less self contained units, and distributed them where they should go.
It's important to be aware that Faulkner was not at all concerned with consistency across his works, or even, at times, between his works and the real world. When asked about a particular example, he said that it was better for the story that way, and that he didn't think anybody would notice or particularly care. Within his own works, some characters might be the same age at two different times or, in at least one case, different ages at the same time.
You may use this if it helps in a scholarly work or critical essay, but be sure and cite the source.
CS = Collected Stories
UCS = Uncollected Stories