John Rankin arrived in Montana Territory in 1869 from his birthplace in Ontario, Canada; he traveled from Fort Benton to Helena and then eventually to Missoula. By 1873, Rankin's carpentry skills and engineering prowess allowed him to become one of Missoula's most successful citizens. He married Missoula schoolteacher Olive Pickering in 1879; Olive Pickering came to Missoula from New Hampshire the year before. They had seven children, six daughters and one son. Between 1880 and 1884, the first four Rankin children, Jeannette, Philena, Harriet, and Wellington, were born at the family's Grant Creek ranch just outside Missoula. John Rankin built a house in Missoula in the mid-1880s and the family started splitting their time between residences. The next three children were born after the construction of the new house, Mary in 1888, Grace in 1890, and Edna in 1893. John Rankin died of Rocky Mountain spotted fever in 1904. Olive Pickering Rankin lived to the age of 93 and passed away on July 26, 1947 in Missoula, Montana.

Jeannette Rankin, John and Olive Rankin's oldest child, was born on June 11, 1880. Her earliest education took place at the country school in Grant Creek near the family's ranch. She attended the University of Montana preparatory school and then the university. She graduated from the University of Montana in 1902. She briefly taught school and dabbled in several other professions, but eventually enrolled at the New York School of Philanthropy in 1908. After graduating in 1909, she took a position at the Washington Children's Home Society in Washington State. Jeannette then attended the University of Washington for a short period before joining the suffrage movement.

The National American Woman Suffrage Association recognized Jeannette Rankin's political skill and hired her as a field secretary. For the next three years, she travelled the country delivering speeches and organizing local grassroots campaigns for suffrage. On July 11, 1916, Jeannette Rankin announced her intention to run for one of the Montana seats in the U.S. House of Representatives. Her campaign was funded and managed by her younger brother Wellington and Belle Fligelman, of Helena, Montana, organized and directed the campaigning. Jeannette Rankin succeeded in becoming the first woman elected to the U.S. Congress. She served in the 65th Congress that convened early in 1917, as a result of the war issue. On April 6, when President Woodrow Wilson's war resolution reached the House, Congresswoman Rankin voted with 55 other members of the House against it. Following her term, she moved to Georgia and bought a small farm. She devoted her time and energy to the peace movement of the 1920s and 1930s, centering her efforts on the Georgia Peace Society, which she founded, and the National Council for Prevention of War (NCPW). Jeannette Rankin lobbied Congress on behalf of the NCPW and other organizations during this time and traveled the country using her celebrity as the first female congress member to advocate for peace.

Jeannette Rankin retained her legal residence in Montana, although she continued to live primarily in Georgia. In June 1940, she announced her candidacy for a second term in the U.S. House of Representatives and defeated her opponent, Jerry J. O'Connell. Her campaign was overtly anti-war, which resonated with many Montanans. After the Japanese attack on Pearl Harbor, President Roosevelt called a special session of the 77th Congress on December 8, 1941. Congresswoman Rankin cast the single "no" vote against war with Japan, which effectively killed her political career. Following her second term, she continued her work in promoting pacifism and peace, traveling the world through the 1950s and 1960s. Jeannette Rankin remained active and politically engaged until her death on May 18, 1973 in Carmel, California.

The second oldest Rankin child, Philena, was born on October 6, 1881. She died from an unknown illness (later believed to be a burst appendix) in 1890. The third Rankin daughter, Harriet (or Hattie), was born on February 20, 1883. She also attended the school in Grant Creek and the University of Montana, like her older sister, but continued here education at Wellesley College in Massachusetts. She married mining engineer Oscar Sedman in 1907. The couple had two daughters, Mary Elizabeth and Virginia. Oscar Sedman died during the influenza pandemic of 1917. Harriet Sedman worked as the Dean of Women at the University of Montana in Missoula for many years before remarrying in 1935 to Grant McGregor. The couple relocated to London, England and Hattie eventually worked for the American Red Cross in London throughout World War II. Hattie Rankin Sedman McGregor died in 1979 in Washington D.C.

Wellington Rankin was born on September 16, 1884. After graduating from the University of Montana in Missoula with a degree in science, he attended Harvard University in Massachusetts, receiving a bachelor's degree in 1905 and a law degree in 1909. Wellington Rankin began his law career in 1909 in the offices of Thomas J. Walsh and Cornelius B. Nolan in Helena, Montana. In 1910, he married Elizabeth Wallace of Helena; the marriage ended in divorce in 1912. Wellington Rankin opened his own law practice in 1911 and specialized in industrial accident cases, representing many workers injured in mines and on the railroads.

Wellington Rankin first became involved in politics in 1914 when he ran unsuccessfully for the state legislature as a Progressive Party candidate. Two years later he was campaign manager for his sister, Jeannette, in her successful run for the U.S. Congress. In 1920, he was elected Montana attorney general and served in that post until 1924 when he was appointed to fill a vacancy on the Montana Supreme Court. After an unsuccessful run for governor in 1928, Wellington was appointed U.S. district attorney by President Calvin Coolidge, and was reappointed by Herbert Hoover in 1930. He ran unsuccessfully for public office several more times, including U.S. Senate in 1942 and 1948, and U.S. House of Representatives in 1952.

In addition to his law practice and his political campaigns, Wellington Rankin owned many large ranches, including the Avalanche Ranch, the Birch Creek Ranch, the Stafford-Floweree Ranch, the Miller Brothers Ranch, and the 71 Ranch. Wellington Rankin was also a partner in several businesses including the Placer Hotel in Helena and the Montana Ready-Mix Company in Missoula. In 1956, he married Louise Replogle, an accomplished member of his law firm and active political figure. Wellington Rankin died June 4, 1966, at the age of 81, in Rochester, Minnesota.

Mary Rankin was born August 30, 1888. She also graduated from the University of Montana in Missoula. She taught English and married Herbert Bragg in 1916. They had two children, Kenneth and Mary Jane. Mary Rankin Bragg passed away in 1971 at the age of 83 in San Marino, California. Grace Rankin was born on November 25, 1891. She also attended the University of Montana in Missoula. Grace married Thomas Kinney in 1913 and the couple had three children, Janet, John, and Thomas. Grace Rankin Kinney passed away in 1954 in Chicago, Illinois.

Edna Rankin was born on October 21, 1893. She was educated at University of Montana, the University of Wisconsin, and Wellesley College. After graduating from Wellesley in 1913, Edna attended and graduated from the University of Montana Law School. She also passed the Montana Bar Exam, but never practiced law. Edna Rankin married John McKinnon in 1919 and the couple had two children, Dorothy and John. Edna and John McKinnon eventually divorced, and Edna worked for the Resettlement Division in Washington D.C. for several years until she devoted her life to family planning education in the United States and abroad. She worked for the Margaret Sanger Research Bureau and became the executive director of Chicago Planned Parenthood from 1947 to 1957.

In 1957, Edna Rankin McKinnon went to work for the Pathfinder Fund. The organization sent her to Asia, Africa, and the Middle East to promote birth control, women's health, and family planning. She retired in 1966. Edna Rankin McKinnon died in Carmel, California in 1978.