A Monster Calls was filmed in Spain, United Kingdom, United States of America.
Heights Church
In movie
Scene where Conor O'Malley goes to the big tree.
Real
Scene was shot St Thomas' Church is also known as Heights Chapel. It was build in 1765. The tree in the movie, next to the church does not exist.
Oldham
Bridge Street crossing
In movie
Scene where On their way to the hospital Conor and his grandmother have to wait for the train to pass. Conor tells his grandmother he's sorry.
Real
Scene was shot at the Bridge Street railroad crossing in the small town of Ramsbottom.
Bury