Lucy Plourde, 75, died at the crash scene.
Maine Department of Public Safety spokesman Stephen McCausland said the rollover happened around 1 p.m. Thursday afternoon in the northbound lanes of Interstate 95 in Edinburg.
Edward Plourde, 79, of Howland was the driver, McCausland said. He drifted off the road and it overturned. He was taken to Northern Lights Eastern Maine Medical Center with serious injuries.
On Thursday afternoon, Plourde was listed in critical condition, a hospital spokesman said.
One of the northbound lanes was closed after the crash while authorities worked to reconstruct the scene.
Maine State Police are asking anyone who saw the Plourdes' 1997 Ford Crown Victoria immediately before the rollover crash to call the Bangor barracks at 973-3700.