Pentagon officials said Spc. Vincent Sebastian Ibarria, 21, from San Antonio, Texas had died on Friday in a vehicle rollover in Farah near the Iranian border.
Additional details about the death were not immediately provided as the incident was said to be still under investigation.
The US soldier was the ninth serviceman to die in Afghanistan this year.
As many as 2,450 US servicemen have so far been killed since the US and its allies began invading Afghanistan in 2001, according to the latest figures provided by icasualties.org, a website that tracks fatalities and other data in Afghanistan and Iraq.
The recent incident took place amid reports of a decline in violence and attacks on foreign forces following a peace agreement between the US and the local Taliban militant group.
The US-led invasion toppled the Taliban regime in Afghanistan, which was accused of harboring the al-Qaeda terror group, but it has failed to end the Taliban’s militant operations across the country to this day.
The Taliban now control or hold influence over more Afghan territory than at any point since that time.