Texas– Brooks County Sheriff Urbino Martinez says the van, designed to hold 15 passengers, was top-heavy and tipped over when the driver lost control on a curve.
Nathan Brandley of the Texas Department of Public Safety put the immediate death toll at 11 with more than a dozen others injured.
Encino is a community of about 140 residents about 2 miles (3.22 kilometers) south of the Falfurrias Border Patrol checkpoint.
The crash happened shortly after 4 p.m. Wednesday on U.S. 281 in Encino, Texas, about 50 miles (80 kilometers) north of McAllen.
Martinez said he believed most of the passengers were illegal immigrants.