William Jefferies Jr.

William Jefferies Jr. was an English Mormon pioneer and early settler of the American frontier.

Jefferies was educated privately in England, joined The Church of Jesus Christ of Latter-day Saints (LDS Church) there in 1856, served for a time as a missionary, and emigrated to Utah Territory in 1856, crossing the plains in Joseph W. Young's pioneer company. Jefferies located in Grantsville, Utah, as tithing clerk upon arriving in Utah, and later was involved in other endeavors there. Jefferies was one of the leading men in Grantsville in the latter half of the 19th-century, involved in almost all business ventures in that city and served as one of its earliest mayors.