A number of homes were evacuated on Tullyveagh Road shortly after 7pm on Friday evening, after a number of suspicious object were reported to police.
Army Technical Officers were called to the scene and police have subsequently said that a number of firearms and ammunition were found buried there.
It is understood police were still working in the area until Sunday afternoon, but the find is thought to date back many years.
A spokesperson for the PSNi said today: "Police have recovered firearms and a quantity of ammunition during a search operation in Cookstown.
"The search was implemented after a member of the public raised concerns about objects he had discovered at Tullyveagh Road on Friday, April 7.
Detective Inspector Will Tate said: "The items we have recovered include several rounds of ammunition and a handgun.
"The condition of the items and other evidence gathered at the scene would suggest they have been buried at that location for many years. They have now been sent for forensic testing.
"Our enquiries into this find are at an early stage and we would encourage anyone with knowledge of the items or any information that could assist the investigation to get in touch with detectives by calling 101, quoting reference number 1070 07/04/17."
Information can also be given anonymously to the Crimestoppers charity by calling 0800 555 111.