The estimate from the International Organization on Migration's Missing Migrants Project includes 214 men, 20 women and four children. The other 138 could not be identified from their remains. Others likely died, but their remains have not been found, Anadolu Agency reported.
The vast majority of those who perished were from the Americas. Only two, who hailed from South Asia, did not come from the region.
The data comes amid US President Donald Trump's hardline approach to immigration, both illegal and legal, including a crackdown on asylum regulations.
Trump's immigration policies have prompted backlogs at official ports of entry for individuals seeking asylum, leaving many to either wait in Mexico for months while their claims are processed or attempt to cross the border illegally.