[1] Markland was elected Fellow of the Society of Antiquaries of London in 1809, and from 1827 to April 1829, when he resigned the post, acted as its director.
[2] In a 2023 article by The Guardian, Markland's contributions to the West India Interest as its secretary and solicitor were described as "pivotal to pro-slavery politics" in Britain.
[3] Also a supporter of church societies, Markland was entrusted by Mrs. Ramsden with the foundation of mission sermons in Cambridge and Oxford, and while he was resident in Bath three ladies, the Misses Mitford of Somerset Place, selected him for the distribution of £14,000 in charitable works in England and the colonies.
[1] Markland wrote:[1] Markland edited for the Roxburghe Club in 1818 a volume of Chester Mysteries, de deluvio Noe, de occisione innocentium; assisted with George Ormerod's History of Cheshire; aided John Britton in his Beauties of England; and contributed articles to the Censura Literaria, the major one being on William Mason and to Notes and Queries.
[1] On 24 September 1821 Markland married, at Marylebone Church, Charlotte, eldest daughter of Sir Francis Freeling, who died on 9 October 1867.