Friends who bonded in school, on the sports field and in college lecture halls
It only takes a quick look through their online profiles to see the holiday snaps, the shared nights out and the close bonds.
The students directly affected by the Berkeley tragedy are made up of two groups who came together to enjoy a summer of sun, fun and work in San Francisco.
They mostly hail from south Dublin and while some were lifelong friends, others are more recent acquaintances.
Olivia Burke and Ashley Donohoe, both of whom died, are first cousins living on either side of the Atlantic until the J1 programme gave them an opportunity to spend time together.
Others had exchanged passes and tackles on the rugby and football fields, while some met in college lecture halls and laboratories.
Olivia, who was studying in IADT in Dún Laoghaire also died alongside her Loreto Foxrock schoolfriend Eimear Walsh. Both had found work in the same restaurant, Hana Zen, in San Francisco.
They were sharing the apartment in Library Gardens with Aoife Beary. It is understood that the group were celebrating Aoife's 21st and had invited several other students living in the complex over to apartment 405 for the party.
Olivia's friend, Lorcán Miller, who was studying medicine in UCD, was one of those who joined the celebration and lost his life. He was also in the same college year as Eimear.
Aoife Beary is from Blackrock and was in a critical condition last night with her parents by her bedside.
Hannah Waters is also friends with the girls and was still fighting for her life last night.
Niccolai Schuster, another UCD student and fomer graduate of St Mary's College in Rathmines, lost his life alongside his classmate Eoghan Culligan.
The pair had played together with Bushy Park Rangers and, through their days on the field, had formed strong bonds with Sean Fahey, Conor Flynn and Jack Halpin.
Jack, who graduated from UCD, managed to break the fall of another friend, Clodagh Cogley, and has been hailed as a hero for his brave actions.
They were both in various stages of recovery last night.
As was Niall Murray, who is understood to be recovering from his injuries.