Jeanette Vizguerra, 44, sought refuge in the First Unitarian Society church after federal officials denied her request for "stay of removal" on Wednesday.
Her immigration lawyer, Hans Meyer told Reuters that she had received five previous stays because she was the victim of an unspecified violent crime and has a pending visa application.
Vizguerra has three children, aged 6, 10 and 12, who are American citizens and an adult daughter, born in Mexico, who holds a work visa.
An immigration judge ordered Vizguerra's deportation in 2009 because of two criminal convictions, one for holding false identity documentation and one for illegally entering the US after she returned to Mexico for her mother's funeral.
At a press conference this morning, Vizguerra said that she had not made the decision to seek refuge in the church lightly.
"I was thinking about it for weeks. But I think that I made the right decision in coming here, instead of going to the immigration office today," Vizguerra said through an interpreter during a news conference at the church.
Since Donald Trump took office, a number of churches across the US say they're preparing to offer sanctuary to illegal immigrants.
"It is our position as a people of faith that this is sacred, and faithful work," said Rev Mike Morran during the news conference, "We know Jeanette. We know her to be an honourable human being."
But the church is facing criticism from some for breaking the law.
Jessica Vaughn, policy director at the Centre for Immigration Studies told NPR: "It is illegal for anyone to deliberately and knowingly shield an illegal alien from detection by federal authorities.
"Potentially these church leaders could be placing their parish at risk for prosecution and fines. I hope it won't come to that."