The widower of the Irish immigrant who tragically died in a swimming accident has paid tribute to his wife as a “wonderful mother”.

Jenny Gallagher (46), originally from County Meath, drowned in a swimming accident while on a family holiday in Iowa.

A devoted mother to her son, five-year-old son Jack, Gallagher was a nurse who had most recently treated the victims of the Aurora,Colorado shooting massacre.

She was among the medical staff of University of Colorado Hospital who met with and were praised by President Obama in the aftermath of the shootings on July 22.

In an emotional interview with the Evening Herald, her husband Greg Pender spoke about how the Irish woman “loved saving lives”.

"She worked the morning after the Batman massacre in a very busy unit of the hospital -- so she saw everything really, some really bad injuries,” Pender told the newspaper.

“But she was brilliant at helping people get through their illnesses. She loved treating people who were in bad situations -- it's the type of person she was."

The father spoke of his heartache over the loss of his devoted wife.

"It's hard to put into words how I feel right now. Jenny and I had been married for seven years. She was a wonderful mother to our son Jack. She loved him more than anything in the world. I admired her so much and loved her dearly. We're struggling to cope without her."

Gallagher had previously worked at Our Lady of Lourdes Hospital in Drogheda before she settled in Denver in the 1990s.

“She was so proud to be Irish," Pender explained. “She was so full of life. She worked so hard to get through college and secure a job that she truly loved. But she really cared about her Irish roots and heritage.”

Passionate about GAA, Gallagher was a founding member of the Denver Gaels ladies football club.

The family had traveled to Iowa for a vacation when the tragedy occurred. Pender explained how he and Jack had gone to sleep when Jenny and her friend took a boat out onto Lake Okoboji in the northwestern part of the state.

“She wasn't a very strong swimmer and I suppose she just wasn't able to stay afloat.”

"The hardest thing is I may never know what really happened to Jenny."

Nurse Jennifer Gallagher pictured with her son, JackDenver Gaels