The first Latter-day Saint missionary work done outside the United States was in Upper Canada. Although Oliver Cowdery and Hiram Page came to Toronto in the winter of 1829-1830 seeking funds to finance the publication of the Book of Mormon, the first actually recorded testimony of the Book of Mormon in Canada was by Phineas Young, a Methodist preacher from New York State in the summer of 1830.
Young had received a copy of the Book of Mormon in April 1830 and convinced of its truth, bore testimony of it to a group of Methodist ministers in Kingston in the early summer of 1830. Phineas and his brother Joseph were Methodist preachers on their circuit in Ernestown Township, Upper Canada.
Joseph Smith, Sr. and Don Carlos Smith were the first ordained Latter-day Saint missionaries to preach outside of the United States. They visited Upper Canada in the summer of 1830 and distributed Books of Mormon in villages on the north shore of the St. Lawrence River.
In January, 1832, Brigham, another of the Young brothers, came to Upper Canada to bear testimony of the truthfulness of the gospel to his brother Joseph, and in April 1832 Brigham, Phineas and Joseph Young were baptized in New York State. The brothers returned to Upper Canada as ordained Latter-day Saint missionaries, and baptized the first Canadian converts and formed the first branch of the Church in Canada.
The gospel spread through the area. Joseph Smith preached and baptized in Mount Pleasant, near Brantford, in Upper Canada in October, 1833 with Sidney Rigdon and Freeman Nickerson. Parley P. Pratt came to Toronto in 1836 where he baptized prominent members, John Taylor, Joseph, Mercy and Mary Fielding and William Law. Hyrum Page preached in Upper Canada from 1836 to 1838 and baptized over 1,000 members. Joseph Smith came again to the Toronto area in 1837.
By 1850, approximately 2,500 residents of Canada—most of them from Upper Canada—had joined The Church of Jesus Christ of Latter-day Saints. Most of them gathered with the Saints in Kirtland Ohio, various counties in Missouri, Nauvoo, Illinois and eventually in Utah. By 1861, the census of Ontario listed only 73 Mormons.