90-year-old illegal Irish immigrant Josephine Stout, who had been living in the U.S. since she was a toddler in the 1920s, passed away on Monday just a few weeks before officially becoming an American citizen.

It was only discovered in 1999 that Stout wasn’t a legal US citizen when a routine check into her status file after she applied for public aid found that she was undocumented.

It would take a staggering 12 years and a search across two continents to gather the necessary documents to prove that Stout was, in fact, in the US legally since she was a young child.

"My grandmother always believed in her heart that she was an American," granddaughter Sandi Stout said to the Chicago Tribune on Tuesday morning as she sat in the living room of the North Lawndale apartment she shared with her grandmother Stout.

After the long search to gather Stout’s documents, Breandan Magee, the executive director of the Chicago Irish Immigrant Support social services organization, submitted Stout’s paperwork for naturalization in December 2012.

Ordinarily, a person has to wait five years after receiving a green card to apply for citizenship, but the process for Stout was expected to just take a few months because she had her five years more than ten times over at that point.

As Stout's health was failing, Magee asked immigration officials to take the unusual step of expediting Stout's application in January, said Marilu Cabrera, a spokeswoman at U.S. Citizenship and Immigration Services. The agency was in the process of doing so when Stout died.

Magee said his organization has received donations for Stout and was using that money to pay for her final expenses.

"She was delighted to become a green card holder," Magee said. "Josephine was a woman who showed such great fortitude. In my eyes she was indicative of that fighting Irish spirit you see in so many women of her generation."

Her amazing story was told in the Chicago Tribune. Records show that Stout was born in a poorhouse in Ireland and that she traveled from there in 1923 on the passenger ship RMS Franconia and that she was aged one and a half.

Back then, landed emigrants were considered resident aliens but Stout’s parents never went through the paperwork for her.

That hardly mattered until 1999 when Stout, after falling on hard times due to several family tragedies, applied to have public assistance.

She could not produce evidence of her citizenship other than a social security number and was denied.

Suddenly she was an undocumented immigrant, approaching 70 with seven grandchildren she was raising after her daughter was killed in a robbery.

"What did I know about being from Ireland?" said Stout. "I don't even have an accent. I have always said, 'I am an American, period.'"

She was forced to collect cans as Irish government officials, alerted to the case, tried to find her original birth certificate.