The remains were found between June and September this year in the Fort Peck Reservoir area of Hell Creek, Montana. The area is a famous dinosaur hunting ground.
The discovery of five Tyrannosaurus rex skeletons during a single summer dig in the United States could mean these creatures were more common than previously believed, according to the leader of the project.
One of the huge, carnivorous dinosaurs could also be the largest specimen ever found.
Jack Horner, head of palaeontology at the Museum of the Rockies in Montana, US, described his team's finds as very unusual.
"On average, a T. rex is discovered once every 10 years," he told BBC News Online. "To find five in one summer in one area is very surprising."
Only 20 confirmed T. rex skeletons have been uncovered to date.
Horner, who acted as adviser to Steven Spielberg on the Jurassic Park films, is not willing to be drawn into immediate conclusions about the scientific significance of the discoveries.
Dinosaur evolution
But he concedes that it might mean the huge beasts were more common than previously believed.
The remains were found between June and September this year in the Fort Peck Reservoir area of Hell Creek, Montana. The area is a famous dinosaur hunting ground.
It has rocks that cross what is known as the K-T boundary, the layer where dinosaurs vanish from the geological record about 65 million years ago.
Horner and his team are involved in a five-year survey of the dinosaurs, mammals, invertebrates and fossil plants found in the region.
But they deliberately set out to look for creatures that lived long before the mass extinction - well below the K-T boundary.
Largest ever
"Most people have been interested in the extinction of dinosaurs, but I'm more interested in how they lived and evolved," he said.
Most of the Tyrannosaurus remains have not yet been fully uncovered. Only the parts of three skeletons and most of a fourth have been removed so far. The rest will be extracted next summer.
There is great excitement about one of the specimens in particular. This was discovered by Horner's wife, Celeste, in July.
The skeleton is only partially intact, but the jaw and a few cervical ribs removed late in the digging season seem to indicate that C-rex (as it has been dubbed) could be the largest T. rex ever found - bigger even than Sue, which drew huge crowds to the Field Museum in Chicago when it was put on full public display for the first time in May.
All images courtesy of the Museum of the Rockies