Authorities said a total of 178 people were found in the tractor-trailer truck in the town of Tantima in Mexico's Veracruz state.
Officials said occupants of the truck on Saturday narrowly averted tragedy, realizing at some point that they had been abandoned by the traffickers. A few managed to escape the vehicle and enlist the aid of local residents who gave them food and water.
The Central Americans were then transported by police to a migration center, where they were given medical assistance before authorities began the process of returning them to their countries of origin.
A Mexican military source told AFP that most of the migrants were adults, although there were also a handful of minors found in the truck.
Their rescue comes less than a week after the horrific suffocation deaths of 10 migrants who were trapped in an 18 wheel truck and discovered last Sunday in a Walmart parking lot in San Antonio, Texas.
Authorities said as many as 200 migrants may have been crammed into the trailer found in Texas, many of whom had to be hospitalized. Some survivors fled the parking lot in waiting cars, according to witness accounts.
US Homeland Security Secretary John Kelly in a statement called the "senseless" migrant deaths the result of a human trafficking "network of abuse and death."
"These smugglers have no regard for human life and seek only profits," said Kelly, a retired military general who has been to Mexico twice to discuss immigration, human trafficking and the sprawling cross-border drug trade.
Officials in the United States say fewer migrants are making the perilous overland journey to America from Central American and Mexico in recent months, in large part because of harsh, anti-immigrant rhetoric from US President Donald Trump, who came to power in January.
Migrants from Central America and Mexico willing to make the dangerous trip risk being victimized by thieves, criminal gangs and unscrupulous traffickers who sometimes take their money and abandon them in desperate conditions on either side of the US border.
Veracruz and the surrounding area has become one of the most dangerous regions for undocumented migrants making their way to the United States, according to rights groups, in part because of drug cartels like the notorious Zetas, which often charges a fee before allowing travelers safe passage.
