Upwards of 200 Quinns are expected to turn up this weekend for a big family reunion on the western shores of Lough Neagh.
One of the organisers, Gavin Scott, from Scotland, said he and a few cousins had been talking about organising a reunion for a couple of years.
"Nothing happened for a long time and then we decided just to get on with it," he said.
The reunion in Ardboe Hall on Saturday night will include a buffet and entertainment.
Family members are making the journey from USA, Dublin and Scotland.
Gavin reckons they might be the biggest family in Ireland.
Although he was born and brought up in Scotland, Gavin remembers travelling over and spending the summer holidays in Co Tyrone.
His mum, Mary, left to pursue a nursing career, met his dad, and settled down.
But she never lost touch with her roots.
"All the hotels in Cookstown are booked out with Quinns," said Gavin, who is looking forward to the get together.
"Should be a great evening for us all. One to remember in the years to come."