The Census Bureau's data showed that US exports to Iran during August rose by 400 percent year-on-year to $149.8 million, Tasnim News Agency reported.
In August 2017, the United States exported goods valued at $34.7 million to Iran, according to the report.
In July this year, US exports to the Islamic Republic stood at $35.7 million.
US imports from Iran during August 2018 also increased by 200 percent compared to the figure for the same period last year, reaching $7.1 million.
The rise in US exports to Iran and imports from the country came in spite of Washington's withdrawal from the 2015 Iran nuclear deal and reimposition of anti-Tehran sanctions.
On May 8, the US president pulled his country out of the Joint Comprehensive Plan of Action (JCPOA), the nuclear deal that was achieved in Vienna in 2015 after years of negotiations among Iran and the P5+1 (Russia, China, the US, Britain, France and Germany).
Following the US exit, Iran and the remaining parties launched talks to save the accord.
On August 6, Trump signed an executive order reimposing many sanctions on Iran, three months after pulling out of the Iran nuclear deal.
He said the US policy is to put "maximum economic pressure" on the country.
Trump also restated his opinion that the 2015 Iran nuclear deal was a "horrible, one-sided deal".