A 31-year-old woman who returned to New South Wales from Syria in October has been charged with entering or remaining in an area controlled by the so-called Islamic State group.
Police allege the woman, Mariam Raad, willingly travelled to the region to join her husband in 2014, and was aware of his activities with the terrorist group.
If found guilty, the offence carries a maximum penalty of up to 10 years' imprisonment.
Ms Raad's husband is believed to have died in 2018.
She was charged in Young, in NSW's South West Slopes region.
Four women and 13 children arrived from the Syrian Roj camp to Sydney in October last year.
The women were all married to IS fighters who are now dead or in jail.
At the time Home Affairs Minister Clare O'Neil said the repatriation was informed by national security advice, considering "the range of security, community and welfare factors in making the decision to repatriate".
Ms Raad was charged after a joint investigation between NSW Police and the Australian Federal Police that began when she entered Syria and continued after her return.
The agencies allegedly used newly obtained evidence to charge her.
AFP Acting Assistant Commissioner Sandra Booth said the joint investigation would continue.
"Individuals will be brought before the courts when evidence supports allegations that returned individuals have committed offences in conflict areas," Assistant Commissioner Booth said.
NSW Police Assistant Commissioner Mark Walton said the force had "zero tolerance" for extremism.
"Our investigators methodically gather information and evidence, conduct surveillance and work tirelessly to target criminal activities which pose a threat to the Australian community," he said.
In October the repatriated women released a statement saying they were happy to be back.
"We are willing to do whatever is asked of us by government authorities to ensure the safety of our families and the Australian community and we will fully cooperate with all Australian law enforcement agencies," the women said.
Save the Children Australia, which has been advocating for the return of Australian women and children from Syria, said the charges showed the repatriations would be scrutinised.
"Australia is showing that it is possible to repatriate its citizens while balancing any potential risks and ensuring the safety of the wider community," a spokesperson said in a statement.
"If there is evidence that any of the women have committed crimes then the appropriate place for them to be charged and prosecuted is in Australia, where we can put our faith in the country's robust judicial and national security architecture."
There are still around 40 women and children in Syrian displaced persons camps, yet to be repatriated.
Ms Raad is expected to face Wagga Wagga court on Friday.
