Born in Marietta, Ohio in 1901, Miss Hornbrook crossed the Ohio River in 1913 to settle in Parkersburg. She graduated from Parkersburg High School and Marietta College. Following college, she moved to Stotesburg, West Virginia to teach school. She returned to Parkersburg and worked for Northrup Equipment and later worked for Parkersburg Property Management, where she worked until retirement.
During the 1950s, Miss Hornbrook assembled a group of about twenty-five people to discuss the issue of establishing a humane society for Parkersburg. Miss Hornbrook's desire was to create a better environment for animals in the area, and she led the group's efforts to raise funds and determine a location for the Humane Society of Parkersburg, Inc. Her involvement with the Humane Society did not stop there. She continued her support by serving on the Board of Directors and helping to initiate many of the programs that still continue to be important components in the Society's success, including spaying clinics and youth educational programs.
Miss Hornbrook's involvement went beyond the city limits. She was influential in formulating state legislation regarding animal rights, and she was active in the Humane Society of the United States and the American Humane Society.
In addition to her love for animals, Miss Hornbrook enjoyed writing and expressed her cares and concerns for animals in newspapers, where she wrote a weekly column called Tails-a-Waggin'. She also wrote poetry and played the piano, and she enjoyed traveling.
To ensure continued support for humane societies throughout the state, Miss Hornbrook established the Ruth Hornbrook Memorial Fund within the Parkersburg Area Community Foundation through a bequest in her will. The purpose of the fund is to benefit humane societies in West Virginia, with preference given to the needs of new societies. Through this fund, thousands of dollars worth of grants have been distributed to humane societies across the state. New animal shelters, humane educational programs, and new equipment are a few of the many programs the fund has supported.