Consists of various tributes and dedications made to Sid after his death.

Consists of a material relating to tribute events including a 'Jubilee Tribute' and the 50th Anniversary of the Battle of Passchendale.

Consists of articles Confessions of a Window-Cleaner, As I please, The Timber of Poetry, and Expedition Miner.

The archive comprises mainly correspondence addressed to Sir Walter and his first wife Pauline Lady Trevelyan nee Paulina Jermyn. The letters reflect the couple's interests in natural history, botany, geology, antiquities, travel, temperance, phrenology, art and literature, and include examples from many well known contemporaries.

There is also material relating to the history of the Trevelyan family, accumulated during Walter and Charles Edward Trevelyan's preparation of 'The Trevelyan Papers' for publication.

The archive also features diaries and journals, sketchbooks, notes for speeches and scrapbooks. There is material relating to the North East of England, including proposed railways, Tyne crossings at Hexham and decoration of the Great Hall at Wallington.

Comprising most of family correspondence, with some content relating to estate and property and George Otto Trevelyan's political career. Also includes autographs and cuttings of notable figures.

Family portrait taken on the steps of Wallington, taken for Caroline and George Otto's golden wedding.
Features Caroline and George Otto Trevelyan, their children and grandchildren.

Glass plate negative showing Caroline and George Otto Trevelyan with their three sons and a dog on the steps outside Wallington Hall.

Family portrait taken on the steps of Wallington, taken for Caroline and George Otto's golden wedding.
Features Caroline and George Otto Trevelyan, their children and grandchildren.

Photograph of Caroline and George Otto Trevelyan and their sons on the steps of Wallington Hall. Also features two young women (possibly Elizabeth Trevelyan and Janet Trevelyan).
Image may have been captured to celebrate Caroline and George's golden wedding anniversary.

Portrait of Caroline and George Otto Trevelyan with their sons and their wives.
Original envelope included, with annotations stating this was the first group photograph with Caroline and George's three daughters in law.