On November 12, 1863, Sprague married
Kate Chase, daughter of
Salmon P. Chase, the former Governor of Ohio and current
Secretary of the Treasury. She was considered the belle of Washington. Fifty people were invited to the ceremony, which took place in the parlor of the mansion where she lived with her father. The guests included President
Abraham Lincoln and his entire cabinet (with the exception of
Montgomery Blair, who refused to attend), senators, governors, generals, diplomats, and select congressmen. An additional 500 people were invited to the reception which followed. Sprague's wedding gift to Kate was a tiara of matched pearls and diamonds that cost $5700. As the bride entered the room, the Marine Band played "The Kate Chase March" which composer Thomas Mark Clark had written for the occasion. There was much speculation in Washington leading up to the wedding – and by historians afterward – that Kate Chase's attraction to Sprague may have been monetary, as her father was losing money by serving as Treasury Secretary, and had a burning desire to be President, which required sufficient funds to mount a campaign. Sprague was not educated, having left school early to join the family business, and was small, thin and not particularly attractive by the standards of the day. He was, however, very rich. • William "Willie" Sprague V (1865–1890), who died by suicide at age 25 in 1890. • Ethel Chase Sprague (1869–1936), who married Dr. Frank Donaldson (1856–1906). William's financial and political fortunes rapidly deteriorated in 1873, with the financial panic. His holdings were extensive both in Rhode Island and nationally. The death of his father-in-law, Salmon P. Chase, in the same year who had become
Chief Justice of the United States, added to his family problems. Severe setbacks occurred to the A. & W. Sprague Company following the
Panic of 1873.
Marriage Likewise, the Spragues' marriage unravelled as William began to drink more, had affairs with other women and began to criticize Kate's spending. Kate allegedly had an affair with New York senator
Roscoe Conkling. According to popular rumor, in 1879 Sprague chased Conkling off his Narragansett estate after catching him with Kate, thus ending the alleged affair.
Canonchet In 1850, Sprague purchased the William Robertson farm in Narragansett, which was known to have once been the location of the summer campsite of Narragansett
Sachem Canonchet.
Second marriage Following his divorce, William Sprague married Dora Inez Calvert (1859–1938) of West Virginia in
Staunton, Virginia, in 1883. He regained his interest in politics to become the first
Narragansett, Rhode Island Town Council President in 1900. On October 11, 1909, a fire destroyed the Sprague mansion, including Sprague's diaries and other valuable artifacts. The Spragues moved to Paris. During World War I, they opened their apartment as a convalescent hospital for the wounded of all nationalities. == Death and burial ==