This collection highlights a small portion of the Macomb family's history between 1806 and 1892. The collection is composed primarily of family letters, however a large portion of the collection comprises of letters and documents pertaining to Major General Alexander Macomb's military career and personal life. This includes but is not limited to a letter of intent addressed to President John Quincy Adams seeking a position as Major General. The letter also mentions the likes of Army Commander Winfield Scott, Statesman John C. Calhoun, and General Andrew Jackson. Another of Macomb's letters serves as permission and instructions to Captain Benjamin Bonneville regarding Bonneville's request to further explore the western portion of the United States, specifically the Oregon Trail. This expedition would eventually broaden the path for westward expansion. Additional materials include General Macomb's Last Will and Testament, a typed summary of his life and career, a letter to General Johnathan Williams describing the events leading up to the Battle of Plattsburgh and the battle itself, and a letter to the United States Court of Claims from attorney's acting on behalf of Harriet Macomb, second wife and widow of General Macomb.
The Catherine Macomb series contains letters written by Catherine Macomb, Alexander Macomb's first wife. The series includes six letters written to various friends and family members over a period of fifteen years between 1806 and 1821. This includes a December 10, 1814 letter written by Catherine to Maria Bleecker Miller describing her intentions to reunite with her husband, General Macomb, shortly after his September 11, 1814 victory at Plattsburgh (also known as the Battle of Lake Champlain). This victory was a defining moment in the War of 1812 as it led to the signing of the Treaty of Ghent which ended the war on December 24, 1814. The series also contains letters addressed to Elizabeth Spencer (Eliza or Mrs. Cass), wife of Lewis Cass, first governor of the Michigan Territory. Catherine also authored a letter in which she mentions Commodore Isaac Chauncey. The remainder of the collection is comprised of letters authored by or addressed to various associates and family members including family friend Henry Authon, General Macomb's sister Jane Macomb, his daughter Jane Octavia (Macomb) Miller, Maria Bleecker (Mother-in-law to Jane Octavia (Macomb) Miller)),and later generations of the family. These letters chiefly discuss family ties and contain general well-wishes and goings on.