This series comprises correspondence sent to other members of the Bell and Richmond families but which was held alongside Charles and family's papers. The sub-series are as follows:

CPT/6/1 - Letters to Hugh Bell and Florence Bell nee Olliffe from and about Mary Katharine Trevelyan nee Bell CPT/6/2 - Letters to Elsa Richmond nee Bell from Mary Katharine Trevelyan nee Bell CPT/6/3 - Letters to various Bell family members from Mary Katharine Trevelyan nee Bell

Further correspondence from members of the Bell family can be found in this collection at CPT/2/5, CPT/2/6 and CPT/2/7.

This series comprises content accumulated by Charles during his lifetime and includes correspondence and papers relating to his work as a Member of Parliament, Cabinet Minister and managing the Wallington Estate.

There is also substantial content relating to his personal life, including his childhood and education, family and domestic matters and personal interests.

Photograph albums and scrapbooks containing photographs of and ephemera relating to the Trevelyan family. Also includes content relating to Mary Katharine Trevelyan's relations, the Bell and Richmond families.
Many of the volumes feature annotations, mostly in Mary Katharine Trevelyan's hand.
The main series of numbered volumes is missing a Volume 4, however annotations in Volume 5 state that this was an error made during binding, and there was no Volume 4.

Family portraits and landscape images of the Wallington Estate.

These correspondence files begin prior to Charles and Mary's marriage, and continue throughout their lifetime. During the early years of their marriage the couple communicated by letter daily while separated - often while Charles attended Parliament staying at the family's home in Great College Street and Mary remained at Cambo House or visited relatives. The letters include discussion of the couple's relationship, news of their children and other family and friends, details of their work and personal interests and domestic arrangements. Later letters include discussion of the management of the Wallington Estate. There are letters from trips overseas, including Russia, Germany and Sweden.

This series comprises content accumulated by Mary during her lifetime and includes correspondence and papers relating to her involvement with numerous organisations including the Women's Institute, Women's Liberal Federation and her position as a Justice of the Peace.

There is also substantial content relating to Mary's personal life, including her childhood, family and domestic matters and personal interests.

This series comprises correspondence sent to other members of the Trevelyan and Philips families but which was held alongside Charles and family's papers. The sub-series are as follows:

CPT/5/1 - Letters to George Otto and Caroline Trevelyan nee Philips from and about Charles and family CPT/5/2 - Letters to George Otto and Caroline Trevelyan nee Philips from various correspondents CPT/5/3 - Letters to Robert Calverley Trevelyan from Charles CPT/5/4 - Letters to various Trevelyan family members and related papers

Further correspondence with George Otto and Caroline Trevelyan can be found in this collection at CPT/1/9 and CPT/2/8.