William Sears Riggs was a son of John Riggs and Mary Gilman Riggs. He was born March 19, 1830, in Quincy, Putnam County, Indiana. He came west, stopping in Salt Lake City, during the California Gold Rush of 1849. He emigrated to Utah in 1849 or 1850, making him a Utah Pioneer. He moved to southern Utah in 1852. He married Sarah Reeves (born September 28, 1837; daughter of William Reeves and Frances Long Reeves) on February 1, 1855, in Cedar City, Utah. They had 10 children: Sarah Frances Riggs Littlefield, Mary Elizabeth Riggs Wixon, Malissa/Mellissa Ann Riggs Ingram, Caroline Jane Riggs, Emma Lovina Riggs Griffin, William Reeves Riggs, Andrew Jackson Riggs, Amanda Ellen Riggs Griffin, Malinda Isabelle Riggs Bryce, and Roselia Riggs Ahlstrom.
William Sears Riggs was among the six families who founded Toquerville, Utah, in 1858. The other family heads were Joshua T. Willis, John Willis, Samuel Pollock, Josiah Reeves and Willis Young. All were interested in raising cotton. (Woodbury, "A History of Southern Utah an its National Parks," Utah Historical Quarterly, 12/3-4 (Jul.-Oct. 1944), 147.)
William Sears Riggs was an original settler in Kanarra (later Kanarraville), Utah, in 1862. The other heads of families were William R. Davis, Richard Palmer, Samuel Pollock, James Davis, Elisha H. Groves, John H. Willis, Sidney Littlefield, Edward Littlefield, Josiah Reeves, and Rufus Allen. (History of Iron County, 174.)
Riggs was a Private in the 3rd platoon, Volunteer Cavalry Co., 1st Brigade of the Iron Military District and was involved in military reconnaisance and operations during the Black Hawk War, 1866. It is asserted that he participated in the Mountain Meadows Massacre of 1857 as a Private in the Iron County Militia, but his role in the massacre is not known with certainty. He was named in the 1859 federal arrest warrant issued by Judge John Cradlebaugh and was named as a participant in Stenhouse's Rocky Mountain Saints in 1873. However, he was not named by John D. Lee nor mentioned by other witnesses during the Lee trials of 1875-1876. He is not known to have made any statements about the massacre.
William Sears Riggs was a carpenter and held positions in the Mormon church: high councilor of Panguitch stake 1879-1891 and Bishop's counselor of Henrieville ward 1892. He died on May 15, 1923, at age 93 at the home of his son Andrew Jackson Riggs in Panguitch, Utah. He left 83 grandchildren, 152 great-grandchildren, and 22 great-great-grandchildren.