Cavanah was born on September 26, 1871, in Greensboro, North Carolina, to parents Frank and Larue (Cheatham) Cavanah.[1] Frank Cavanah traveled to Idaho Territory that year to pursue mining interests in Rocky Bar and Hailey, and he remained in Idaho until his death in 1897.[1] Larue Cavanah died in 1872, leaving the infant Charles in the care of family members.[1] Cavanah attended public schools in North Carolina and in Texas, where he also worked as a store clerk.[1] In 1892, he moved to Boise, Idaho, and became court crier of the Idaho Supreme Court.[1] Cavanah read law in the office of William Borah, and he lived at the home of Judge Joseph W. Houston.[1] After admission to the bar in 1895,[2] Cavanah joined the partnership of Borah, Cavanah & Blake.[1] Later, Cavanah became senior partner in Cavanah, Blake & McLane.[3] In 1897, Cavanah was elected Boise city attorney, and in 1906 he was elected to represent Ada County, Idaho in the Idaho State Legislature.[1][4]
