Large, often confused, crowds formed ragged lines behind police barricades where officers handed out color-coded wristbands. Blue meant they were from Ontario and could remain. Orange indicated they had to provide more proof to avoid ejection, and white meant they had a week to leave.
"When my husband gets out of jail he can bring my marriage certificate; will that count?" asked one tearful woman.
Another resident, clearly confused, seemed relieved to get a white band -- not understanding it meant she had to leave.
Pattie Barnes, 47, who had her motor home towed away last week, shook with anger.
"They are tagging us because we are homeless," she said, staring at her orange wristband. "It feels like a concentration camp."
Ontario officials, citing health and safety issues, say it is necessary to thin out Tent City. The move to dramatically reduce the population curtails an experiment begun last year to provide a city-approved camp where homeless people would not be harassed.
Land that includes tents, toilets and water had been set aside near Ontario International Airport for the homeless. Officials intended to limit the camp and its amenities to local homeless people, but did little to enforce that as the site rapidly expanded, attracting people from as far away as Florida.
"We have to be sensitive, and we will give people time to locate documents," said Brent Schultz, the city's housing and neighborhood revitalization director. "But we have always said this was for Ontario's homeless and not the region's homeless. We can't take care of the whole area."
Officials believe the local homeless number about 140, less than half of those currently in residence. Schultz wants to reduce Tent City to 170 people in a regulated, fenced-off area rather than the sprawling open-air campsite it has become.
No other city has offered to take in any of the homeless who Ontario officials say must leave.
"So far I have heard nothing," Schultz said.
Even before the large-scale action Monday, police last week moved out parolees and towed about 20 dilapidated motor homes. A list of safety rules, including one banning pets, has been posted. The city says there is a threat of dog bites and possible disease from the animals.
The no-pet order caused widespread anger and tears Monday as some homeless people said they could not imagine life without their dogs. Many have three or four and vowed to leave Tent City before giving the dogs up.
"I will go to jail before they take my dog," said an emotional Diane Ritchey, 47. "That's a part of me as much as anything. The dogs are as homeless as we are."
Cindy Duke, 40, hugged Ritchey, who was sobbing.
"I had to give up my 6-year-old son because I was homeless and I'll be damned if I give up my dog too," Duke said.
Celeste Trettin, 53, rolled up in a wheelchair. She and her husband have an Ontario address but have lived for years in a truck, parking wherever they found a safe place. Trettin, who got an orange wristband, said she believed she would be able to find the paperwork to prove she was from Ontario.