A cougar was reported just south of Leslie Groves Park along the Columbia River in Richland on Tuesday evening.
The call was reported to Richland police about 8:20 p.m.
The mountain lion was reportedly north of the restrooms in the natural area along the river near the 1400 block of Hains Avenue, which is north of Howard Amon Park.
Richland police went out to the area, but were not able to find a cougar.
They notified agents with the Washington State Department of Fish and Wildlife.
The cougar could be long gone this morning, said Jason Janosky, a Richland park ranger.
Male cougars, also called mountain lions, can range over an area of 50 to 150 miles, he said. Or it could be a young male cougar passing through looking for territory.
The park remains open, but Janosky recommends people be alert.
They may want to leave pets at home. If they do bring dogs, they should obey leash laws and also keep dogs in front of them where they can keep an eye on them, he said.
Children also should be where an adult can see them, including walking in front of adults.
Cougars are spotted occasionally in Richland.
Last year Janosky saw one in the Chamna area of Richland near the Yakima River, he said.
There also have been reports of cougars this year in Richland near Leslie Canyon in south Richland and crossing Keene Road near Yokes.
Do not run if you see a cougar, Janosky cautioned.
Stand tall and keep eye contact with the animal, he said.
State fish and wildlife officials also recommend making as much noise as possible to chase the cougar away.