annually on September 29th (since 1786)
Archibald Hunter on September 29th, 1786
Goose Day was unofficially started in 1786 in Pennsylvania in the Juniata River Valley, and has officially been celebrated in Mifflin County since 1973, and Juniata County since 1976. It stemmed from Michaelmas, a Christian holiday celebrating the archangel Michael, and a day when geese are often eaten. In 1786 a Dutchman named Andrew Pontius hired an Englishman named Archibald Hunter. In their contract it said that accounts would be settled each year on September 29. When the day came, Hunter showed up at Pontius' door with not only his accounts, but with a goose under his arm. As Pontius was confused, Hunter explained to him how the goose signified good luck for the following year, and how in England he had celebrated Michaelmas. Goose Day became popular in the Juniata River Valley and eventually became an established day in the two aforementioned counties. Festivals take place in those counties on the day, and events happen on the week surrounding it.
How to Observe
If you happen to be in Mifflin or Juniata County, there are many activities happening during the day. There are goose specials at restaurants across the area and an annual run. You can find more information about activities here. If you aren't in the area, the best way to celebrate the day is by eating goose. If you have children you could read them some Mother Goose nursery rhymes, or play "Duck, Duck, Goose" with them.