At Rebecca's death in 1897, Judge John Rowan's estate entered nearly 50 years of being unsettled. The Judge's house and lots in Louisville, the Federal Hill farm, in addition to properties owned elsewhere and sums of money were equally divided amongst the heirs of John Rowan senior. John Jr. & Rebecca's daughter Margaret "Madge" Rowan Frost received half of the Federal Hill farm and mansion. In 1895, Madge married John Frost and together they traveled the United States and Europe until his death in 1915.
Madge was the last owner of Federal Hill Mansion. Madge primarily used the Federal Hill mansion to entertain friends. Federal Hill retained its popularity amongst Americans who continued to recognize the home as contributing to the inspiration of Stephen Foster's song "My Old Kentucky Home."
On March 20, 1920, the Commonwealth of Kentucky recognized the importance of retaining Federal Hill as a museum to educate the public in regards to 19th century life, the influence of the song, "My Old Kentucky Home, Good-Night!" and "enshrine" the property for future generations. Under House Resolution number 42, a commission was formed to investigate and secure the property for a state park. Initially, Madge offered the mansion and farm for $75,000; far less than the farm's appraised value. Ultimately, $65,000 was raised to purchase the house, adjoining land, and interior furnishings. The Commonwealth of Kentucky began work immediately to completely restore the house. On July 4th, 1923, Federal Hill officially became "My Old Kentucky Home" with more than 15,000 onlookers cheering the preservation of the home.
After selling Federal Hill, Madge Frost moved to Louisville, Kentucky. Madge later returned to Bardstown and purchased a home across the road from Federal Hill. Madge contracted pneumonia in late January of 1925 and died on February 4th and was buried in the cemetery at Federal Hill.
In 1928, Stephen Foster's abolitionist inspired ballad "My Old Kentucky Home" in its entirety, containing three verses and one chorus, was made the Commonwealth of Kentucky's state song. By 1959, the park grew in popularity and new attractions were added including the "Stephen Foster Story," an outdoor musical that is considered to be the longest running outdoor musical in America, and is now the official outdoor musical of the Commonwealth of Kentucky. In 1975, the park's attendance reached over 450,000 people annually.