This collection consists chiefly of letters by Sergeant John Blankenship Duncan to his wife, Adaline Gelina Wright Duncan, and other relatives that document his military service during the Mexican War, 1846-1847, as well as other papers, 1844-1853. Duncan served in the 1st Illinois Infantry Regiment, Company G, which also included his brothers-in-law Second Lieutenant Isaac Selby Wright and Private Andrew J. Wright, who co-sign some letters, as well as his nephew, James Monroe Childers.
Correspondence by Duncan from within the United States documents the organization of the 1st Illinois Infantry Regiment in Alton, Illinois, in June 1846, and its subsequent movement to New Orleans, Louisiana, as well as Camp Irwin and Camp Crockett in Texas.
In Mexico, Duncan describes the activities of the soldiers in Santiago de la Monclova, Parras de la Fuente, and San Juan de la Vaqueria, as well as Camp Taylor near Monterrey and Camp Buena Vista near Saltillo. A lengthy letter by Duncan to his brother-in-law Henry C. Wright describes the Battle of Buena Vista. A letter written by Childers in Monterrey in February 1848 discusses his plans for after the war.
Letters by Adelina Duncan to her husband occasionally include notes by her brothers and sisters, including Alexander M. Wright and Nancy S. Wright. The collection also includes a letter by an extended family member, James Rutherford Luttrell. These letters discuss activities and events in Morgan Country, Illinois, as well as reactions to the Mexican War on the home front.
The collection includes a letter from James Ewell Heath, Commissioner of Pensions in the Department of the Interior, to United States Representative Richard Yates in December 1852. It attests the service of Captain William Thomas Givens during the Black Hawk War and his entitlement to a land grant.
Other material in the collection includes the discharge papers of Isaac Selby Wright from the 1st Regiment of the Illinois Volunteers signed by Moses Turner on October 1, 1844, for his service during the Illinois Mormon War. Two election decrees by Illinois governors relate to public offices held by Duncan in Morgan County, including a decree by Augustus C. French for Justice of the Peace in December 1849, and a decree by Joel A. Matteson for County Justice in November 1853. An undated list documents members of the immediate Duncan family.