Lancashire Police said a post-mortem examination concluded the 33-year-old died of head injuries.
The mum-of-two, from Padiham, was last seen getting into a Ford Transit van in Burnley on April 22.
Her body was found by Lancashire Police officers in the Forest of Bowland on Friday evening.
A spokesman for Lancashire Police said: “We can now sadly confirm that the body found in the Forest of Bowland is that of Katie Kenyon.
“Police found Katie on Friday following extensive searches and she has now been formally identified as the missing Padiham mum, 33.
“A Home Office post-mortem examination was conducted yesterday and the cause of death was given as head injuries.
“Our thoughts remain with Katie’s family and loved ones at this difficult time. The family continues to be supported by specially trained officers.
“We would like to thank, once again, all those who helped during the search for Katie.”
Andrew Burfield, 50, of Todmorden Road in Burnley, has appeared in court charged with murder and will face trial in November.