Emergency services are in Avenham Park after a man was reportedly stabbed in the leg near the Japanese Gardens.
Police and ambulance crews attended the park, shortly after 2pm following reports of an assault.
A man in his 20s was taken to Royal Preston Hospital with an injury to his leg and a cordon has been putting in place, LancsLive reports.
Police are using a drone, dogs and horses to search the park.
A police spokesperson said: “We were called around 2.05pm today (Wednesday, June 17) to a report of an assault in Avenham Park, Preston.
“Emergency services attended with a man, believed to be in his 20s, suffering a suspected stab wound to his leg.
“The man has been taken to Royal Preston Hospital for treatment.
“An investigation is underway and enquiries on-going.”