 Seward was born in Auburn, New York.His father, William Henry Seward Sr., had just taken office as Governor of New York when he was born, and his mother, Frances Adeline Seward, was the daughter of Judge Elijah Miller, a law partner of Seward who had built the family home in Auburn in 1816.His elder brothers were Augustus Henry Seward, a brevet colonel in the Paymaster Corps, and Frederick William Seward, who served as Assistant Secretary of State to his father.