Authorities at the United States' border with Mexico have seen a more than 100 percent increase in heroin seizures since 2010, according to government figures.
Data in the DEA's annual National Drug Threat Assessment (NDTA) shows there were 2,524 kilograms of heroin discovered at America's southern border in 2015. In 2010, that number was 1,016, and in 2008 it was 559 kilograms.
The Daily Caller reported on the DEA's findings.
"Most of the heroin smuggled into the United States is brought overland across the Southwest Border (mostly Mexican heroin and some South American heroin) with lesser amounts transported by couriers on commercial airlines (South American, Southwest Asian, and Southeast Asian heroin)," the report reads.
The uptick in the numbers shows that smugglers have largely turned to attempting to bring the illegal drug into the U.S. either on foot or in a vehicle instead of by air, a practice that was more prevalent in past years.
The DEA claims that in 2008, 49 percent of all heroin seizures made by the Department of Customs and Border Protection were on land. In 2015, that number was 81 percent.
Several states experienced heroin outbreaks over the summer, which resulted in deaths and dozens of hospitalizations.
Former INS agent Michael Cutler recently told Newsmax America's sanctuary cities are helping drug cartels push heroin and other drugs into the U.S. market.
"We are washed in heroin and in cocaine," Cutler said. "That garbage is not made here. It's all smuggled into the country, and they move an entire drug organization into the communities to peddle the drug to make certain the money gets back to the cartel."