Re; prisoners, I looked it up and it was Cuba, in the '80s. It was called the Mariel boat lift and it consisted of 125K Cubans, of which 25K were prisoners.
I also looked up caravans during the Obama administration and found this. I couldn't find anything specifically using the word "caravan."
In 2014, Mexico began its Frontera Sur, or Southern Border, policy cracking down on unauthorized immigration via Central America after the Obama administration declared a crisis over the number of migrant children arriving at the border. While the Mexican government had been prioritizing "enforcement as opposed to the protection and asylum" for around the last decade," the 2014 border plan ramped up immigration enforcement efforts, said Daniella Burgi-Palomino, a senior associate at the
Latin America Working Group.
"What we saw in 2014 the Mexican government stepped that up with U.S. support, pressure and funding," she said.
Data provided by the Migration Policy Institute showed that that Mexico has removed more people from the Northern Triangle (Guatemala, Honduras and El Salvador) from its country than the United States every year since 2015.
After removing roughly 77,000 migrants from Mexico in 2013, the nation has removed 91,000 people in 2014, roughly 165,500 in 2015, another 149,000 in 2016 and more than 94,500 in 2017. By contrast, the United States removed roughly 104,500 people in 2013, compared to about 121,800 in 2014, roughly 75,350 in 2015, roughly 76,470 in 2016 and roughly 74,800 in 2017.
Data from January to August of 2018 showed Mexico has deported more than 86,400 people. Those numbers do not include voluntary returns by migrants themselves with the help of immigration authorities in both countries."
https://www.nbcnews.com/news/latino/mexico-faces-conundrum-migrant-caravan-u-s-pressure-mounts-experts-n923606
