Crosthwaite is a Grade 2* listed 12th-century church built on the site of older churches dating to the 6th century. Later additions date from the 16th and 19th centuries. The church is dedicated to St Kentigern, who came to this area in the mid 6th century.
Poet Robert Southey is buried in the churchyard, and a memorial stands in the south-east corner. Southey worshipped at Crosthwaite for 40 years.
In the churchyard, a short stroll from Southey's grave, is the grave of Canon Rawnsley, co-founder of the National Trust. A memorial plaque to Rawnsley is on the wall by the font, just inside the south door of the church. Rawnsley and his wife Edith founded the Keswick School of Industrial Art. It was here that the church gates and the brass decoration on the reredos were designed and manufactured.
The pride of St Kentigern's is a complete set of Tudor consecration crosses, 9 inside the church and 3 outside. Though most of the stained glass is Victorian, several fragments of 12th-century glass remain.
The church is open for visitors from 9.00am to 5.00pm during the summer (BST) and from 9.00am to 2.00pm during the winter.