The festival of Rosh HaShanah (the Head of the New Year) is observed on Tishrei 1, the first day of the Jewish year. It is the anniversary of the creation of Adam and Eve as well as the world.
This year Rosh HaShanah falls on Tuesday September 22 and Wednesday September 23. Both are Yom Tovim. Services both days will begin at 10:30 am.
See below for information about Tashlich.