The raids, which targetted 680 undocumented workers, is believed to be the largest in US history.
US Democratic Presidential hopeful Bernie Sanders has described a mass immigration raid that arrested almost 700 undocumented workers in Mississippi as "evil".
The raids, believed to be the largest in US history come just days after Latino migrants were targeted in Saturday's El Paso shooting.
Seven food processing plants throughout the state were raided by Immigration and Customs Enforcement (ICE) officials on Thursday, leaving children without parents to pick them up from their first day of school.
"I need my dad and mommy," 11-year-old Magdalena Gomez Gregorio told a local TV station.
"My dad didn't do anything, he's not a criminal."
Neighbor Christina Peralta said the girl's mother had been in the country for 15 years and had no criminal record.
Mr Sanders said the country needed to "end the terror inflicted on immigrant communities and bring families together, not tear them apart".
Friends and neighbours took charge of the children and brought them to the Clear Creek Boot Camp, where they spent the night. Community groups also donated food and bedding.
Videos and pictures showed children crying, covering their faces, consoling each other, and seated on the floor eating pizza from napkins.
Jordan Barnes, owner of the Clear Creek Boot Camp, said he hoped to "ease their pain a little bit" by giving the children a place to stay.
"These ICE raids are designed to tear families apart, spread fear, and terrorise communities," another Democratic presidential candidate, Kamala Harris, said.
"These children went to daycare and are now returning home without their parents because (US President Donald) Trump wants to play politics with their lives," she said.
The raids took place just hours before Mr Trump was scheduled to visit El Paso, Texas, to meet with those affected by Saturday's shooting which has been linked to a statement published online referencing a "Hispanic invasion".
Twenty-two people, of mostly Hispanic origin, were killed in the attack at a Walmart department store.
At a news conference on Wednesday, officials said the raids were months in the planning.
"They have to follow our laws, they have to abide by our rules, they have to come here legally or they shouldn't come here at all," Mike Hurst, the US attorney for the southern district of Mississippi, said.
Mexico said 107 of its nationals were among the 680 detained.