Warren Higgins, 67, of Franklin was pronounced dead at the scene, according to Ellsworth Police Chief Glenn Moshier.
Higgins was driving a black pickup truck on Route 1A when he collided head-on with a box truck driven by Michael Moore, 57, of Brewer shortly after noon.
Moore and his passenger, 53-year-old Carl Condon of Troy, were taken to a Bangor hospital with injuries that were not considered life-threatening.
The collision caused Route 1A to be closed for several hours.
Moshier said investigators have not yet determined an exact cause for the crash but he believes rain could have played a factor.
"Particularly on this stretch of road where this milling has been done, it's absolutely imperative that people use extra caution with this heavy rain and avoid standing water and avoid hydroplaning," Moshier said.
Ellsworth police, state police and members of the Ellsworth Fire Department responded to the call.
Officials are continuing to investigate the cause of that crash.