The American generation succeeding Generation X. They are named as such due to their coming-of-age at around the turn of the millenium in some way, shape, or form. A realistic time frame would be early 1980s to mid 1990s. Given that 9/11 was the defining moment of this generation, anyone too young to remember or not born yet would be grouped into the Homeland Generation. Some sources put the end of the Millennial Generation as late as 2003, but as I just said, this is an amazingly meaningless definition.
I was 17 and watching the Twin Towers fall from a TV blaring over the rumble of students in my high school cafeteria.
My little cousin born in 1998 was 3 years old, barely out of diapers and will remember 9/11 like I remember the Challenger exploding.