Some are branding Pope Francis' brief trip as 'tough love' after he criticised Mexico's ruling class for failing to protect people from predatory criminal gangs and rampant corruption.
He urged bishops to get closer to their faithful and ease their suffering, and he also visited some of the country's poorest and most violent areas to shine a spotlight on what daily life is like for people living there.
On the final day of his told the pope made a politically bold move and hundreds of thousands gathered for Mass at a Ciudad Juarez fairground.
A further 30,000 watched via simulcast at a football stadium across the Rio Grande in El Paso, Texas.
Francis also aimed a message north of the border at a time of increasingly tough presidential campaign rhetoric on immigration in the US.
The pope appealed for governments to open their hearts to the "human tragedy" of forced migration, imploring: "No more death! No more exploitation!"
Pope Francis stopped short of calling for the US to open its borders, but he did urge recognition that those fleeing gangland killings and extortion in their homelands are victims.
He said: "We cannot deny the humanitarian crisis which in recent years has meant the migration of thousands of people, whether by train or highway or on foot, crossing hundreds of kilometres through mountains, deserts and inhospitable zones.
"They are our brothers and sisters, who are being expelled by poverty and violence, drug trafficking and organised crime."
Before the Mass, Francis paused at the border for a silent prayer in memory of migrants who died trying to reach the US.
He also blessed several hundred migrants sitting on the other side of the fence.
Flying in from the Vatican on Friday, he landed first in Havana for a historic meeting with Patriarch Kirill of the Russian Orthodox Church, the first such encounter since the schism that divided Christianity a millennium ago, before returning to Rome.