Marriage contract prepared for Rachel W. Johnson prepared by Rinaldo Johnson, 1792

The Garrett collection of Johnson family papers consists primarily of correspondence, bills and receipts, legal documents, and land records from 1762-1958. The collection is arranged into three series: Series I: Personal Papers, Series II: Mixed Materials, and Series III: Land Records.

Series I consists of 14 sub-series based on individual members of the Johnson family, beginning with the oldest represented member of the family, Horatio Johnson (1755-1811), and continuing for three successive generations to the youngest represented family member, Robert Wilkinson Johnson, Jr., (1891-1969). This series includes wills and estate papers, bills and receipts for everyday items and materials, and correspondence regarding land ownership, business, and personal ventures. One item of note is Dr. Thomas Johnson's book of "quack recipes" for various ailments, instructing cures for leprosy, lunacy, and "the bite of a mad dog", among others.

Series II consists of mixed materials that pertain to several Johnson family members, miscellaneous documents and receipts, and items having to do with families related to the Johnsons through marriage, including Fell, Tagart, and Giles. Included in this series are two posters offering $100 rewards for the return of enslaved men named Job and Richard to Rockland, circa 1814 and 1817. The posters describe the men in great detail, particularly Job, who is named on both posters.

Series III consists of land records such as indenture documents, survey papers, and correspondence pertaining to specific tracts of land. Two areas of note include a 1774 indenture for the sale of Turkey Cock Hall, the Johnson family residence, and an 1809 notice of construction for the Falls Road Turnpike.