Conditions in the container illustrated the increasing sophistication of people smugglers with fans and ventilation ports cut into its roof.
The National Immigration Institute (INM) said on Monday the trailer was found in the steamy Gulf coast state of Veracruz. It was on a route often used by smugglers to bring people from southeastern Mexico to the United States border.
The people were in good health and it was unclear why the driver fled, authorities said.
Most of the children were from Guatemala. Migrants who make it to the US frequently pay smugglers to bring their children afterwards.
The institute said the adults were mainly from Guatemala, Honduras, El Salvador and Ecuador.
The children will be put into the custody of Veracruz’s family services system while the others will be processed to determine their legal status in Mexico, INM said.
The conditions in the container illustrated the increasing sophistication of smugglers. The trailer had fans and ventilation ports cut in the roof and the people wore colour-coded bracelets, apparently to identify them as smugglers’ clients.
Last June, more than 50 people died after they were abandoned in a scorching hot tractor-trailer truck in San Antonio, Texas.
In December 2021, 56 US-bound migrants from Central America were killed and dozens injured when the truck they were travelling in overturned in southern Mexico.