The northern part of Blaine County is referred to as the Wood River Valley, though it is in the Magic Valley. The towns of Ketchum, Sun Valley, Hailey, and Bellevue compose the Wood River Valley.
Members of The Church of Jesus Christ of Latter-day Saints immigrated to what is now the Magic Valley in the 1880s. Specifically, they immigrated to today's Minidoka and Cassia County. The Cassia area consists of the towns of Burley, Rupert, Paul, and Oakley, among others.
Twin Falls is the largest economic center of the region. It was founded in 1904. Towns in neighboring counties were established during the following years. With the advent of water, power, and electricity, the farming industry grew, thanks to modern farming methods and modern irrigation. The growth of farming led to a growth in the industries that farms support, and banks, schools, and other city essentials followed suit.
Members of The Church of Jesus Christ of Latter-day Saints (sometimes called the Mormon Church) make up roughly half the population of the Magic Valley. Approximately 25 percent of Twin Falls County, and upwards of 60 to 70 percent in the eastern Magic Valley, is LDS.
There are four stakes in Twin Falls County, one in Jerome County, and one in Gooding County (which covers Camas County as well). Another stake serves Lincoln and Blaine County. Four stakes serve Cassia County and Three cover Minidoka County.
President Harold B. Lee was educated at the now defunct Albion Normal School, 20 miles southwest of Burley, where he earned a teaching degree. Early in his life, Apostle Dallin H. Oaks lived in Twin Falls, until his father's death and his mother's immediate need to obtain an education made a move necessary. His brother Merrill, who served in the Second Quorum of the Seventy, was born in Twin Falls. Another apostle, David B. Haight, grew up in Oakley, and a number of his family remained there (although he, himself, lived elsewhere as an adult). Indeed, Haight's grandfather was a pioneer to the Oakley Valley. Other General Authorities with connections to the Magic Valley are D. Rex Gerratt, a Burley area dairy farmer who served in the Second Quorum of the Seventy from October of 2002 to October of 2007, and is president of the Twin Falls Idaho Temple from 2008 to 2010; and Stanley G. Ellis of the second Quorum of the Seventy, who was raised in Burley.
The Sun Valley Branch, since it is situated near a resort, has hosted General Authorities and general auxiliary officers. Prophets in that area for non-church reasons have been speakers in that area, too.
Due to the area's high membership, Church President Gordon B. Hinckley announced a temple to be built in Twin Falls in the October 2004 General Conference. It was dedicated August 24, 2008, with a cultural celebration held the night before at the Twin Falls County fairgrounds west of Twin Falls in Filer. As tickets to the arena were limited the event was broadcast closed circuit to stake centers in the temple district. Many people also watched the dress rehearsals as well. An open house for media, neighbors, and people of all faiths from the surrounding communities, took place from July 11th to August 16, 2008.