These are some of the deadliest instances of migrant deaths on the southern border.

The bodies of more than 40 people who appeared to have crossed into the United States illegally were found on Monday in one of the worst episodes of migrant deaths on the southern border in recent years.

The journey north for migrants crossing into the U.S. from Mexico is typically dangerous, and sometimes fatal. Smugglers often transport large numbers in trailers, vans or S.U.V.s through remote areas in sweltering weather. And in recent years, dozens of migrants have died in crashes while traveling north.

Here is a partial list of some of the deadliest vehicle chases, single-car accidents or heat-related deaths involving smuggled migrants:

• In 2003, sheriff’s deputies discovered the bodies of 17 migrants, including a 7-year-old boy, inside an overheated trailer truck in Victoria, a city in southern Texas. Officials located the trailer at a truck stop and found that the migrants trapped inside had attempted to punch air holes out so they could breathe. Another migrant later died at a hospital.

• In 2012, a Ford pickup carrying more than 20 undocumented migrants struck two trees, killing 15 people.

• Ten men died in San Antonio in 2017 after riding in a tractor-trailer packed with as many as 200 migrants. For hours, they did not have water, fresh air or food, resulting in nearly 30 other people hospitalized. The driver was sentenced to life in prison.

• A S.U.V. packed with undocumented migrants crashed in rural South Texas in 2019 after it was chased by police. Six people died. The vehicle had veered into a ditch in rainy weather.

• In March 2021, 13 people were killed in a remote stretch of Southern California when a crammed Ford Expedition drove into the path of a tractor-trailer.

• Last August, at least 10 people died and 20 others were injured after a van crashed in South Texas.

Miriam Jordan and Eliza Fawcett contributed reporting.