Lifetime friends, Carl Sandburg and Thomas Hornsby Ferril corresponded frequently. Sandburg stayed at the Ferril house when he visited, entertaining guests by singing and playing his guitar. Ferril accompanied him on his mandolin.
Ferril introduced Sandburg to Anne Evans. She provided Sandburg intimate details about Governor Evans's relationship with Abraham Lincoln.
Sandburg was a fan of Ferril's poetry. He contributed promotional quotes to be added to Ferril's poetry books and wrote as a fan. He also liked Helen Ferril and helped promote her books, the first and second Indoor Guides to Birdwatching.