The Blake family correspondence (140 items) includes incoming letters to Jonathan Blake of Warwick, Massachusetts, and New York City (around 115 letters), along with a smaller set of incoming letters to Blake's future son-in-law, Ephraim Lyon of New York City (around 15 items). Their outgoing correspondence makes up the remainder of the items.
Jonathan Blake's incoming correspondence, which is dated from 1825-1847, mainly consists of personal letters from his siblings and cousins, though he also received letters from other acquaintances. His family often provided news of their lives in Warwick, Massachusetts, and Northampton, Massachusetts, commenting on subjects such as education, local and family health, and religion. A brief group of letters between Jonathan Blake and his wife Mary in 1838, 1840, and 1843 concerns his attempts to persuade her to join him in Warwick, where he hoped to nurse his fragile health, though she did not wish to leave New York City. After 1847, the correspondence largely consists of incoming personal letters to Ephraim Lyon and Lyon's letters to Mary Blake before their marriage. His friends and family members reported on their social lives in Waterford, Connecticut, and on other subjects, and Lyon wrote to Blake about his romantic feelings for her and, in one letter, the possibility of moving to California to pursue his fortune (August 3, 1852).