Harrison Ford is refusing to allow elk hunting on his property, despite official efforts to reduce numbers in order to protect the local habitat.
Harrison Ford has banned hunters on his 800-acre ranch
The elk population in Jackson, Wyoming, has risen to 5,100, exceeding the state's 4,400 target.
Authorities believe landowners, including Ford, are providing a refuge for the elk, a type of deer.
"(Ford) doesn't want any hunting to take place on his property," said John Kelly, who manages the actor's ranch.
Warning signs have been placed around the actor's property to deter would-be hunters.
"He told me that if I caught anyone to turn them
in," said Mr Kelly.
Wyoming wants to keep the elk population down to protect the cottonwood habitat on the Snake River.
Elk numbers have doubled in the region since the 1980s
There is also the threat of diseases being spread by the elk to the cattle population, as well as potential damage to the cattle's hay stores.
The number of elks has doubled in the Snake River region since the 1980s, according to experts.
"The problem is that a lot of landowners don't allow
permission to hunt," said Mark Gocke, spokesman for the Wyoming Game and Fish Department.
"That's why this particular herd segment has grown so much."