Catherine, or Kate as she was often called, was the daughter of Josiah Lincoln, who was a brother to Abe's father, Thomas Lincoln. She was born in Harrison County, Indiana, in 1817. According to later newspaper reports, Kate, as an old woman, enjoyed telling stories relating to her famous cousin's youth, and one or two reports even suggested that the two were childhood playmates. A more than eight-year difference in age casts doubt on this assertion, but the two families were indeed close. Years later, President Lincoln said that he knew Josiah Lincoln very well and that he considered him an excellent and honorable man.
Catherine Lincoln married John Sullenger in Harrison County in 1836, and a few years later, the couple, along with other Sullenger family members, migrated to Missouri and settled in western Jasper County. The Sullengers lived for many years in the Peace Church community, and two of Kate's children, who predeceased her, were buried in the Peace Church Cemetery. However, Kate's husband and two other children, who also predeceased Kate, were buried in the Sherwood Cemetery.
After her husband died in 1898, Kate sold the old homestead and moved into Joplin around the turn of the 20th century. After Kate herself died on March 11, 1908, her body was taken back to Sherwood for burial two days later.
In a story that appeared in a Joplin newspaper near the 50th anniversary of Kate's death, one of her granddaughters claimed that nobody around Joplin even knew about Kate's connection to President Lincoln until after she died. This seems to be an exaggeration, because it was reported at the time of Kate's death that she was a cousin of the former president. However, it does appear to be true that Kate rarely bragged about her connection to President Lincoln or tried to gain advantage because of her famous relative.
Note: most of the information for this blog post is condensed from an article I did on the same subject a few years ago for Journal of the Ozarks.