Leupp LOOP (Navajo: Tsiizizii) is a census-designated place (CDP) in Coconino County, Arizona, on the Navajo Nation, United States. The population was 951 at the 2010 census.

In 1902 an Indian boarding educational was constructed here, administered by the Bureau of Indian Affairs. It had been closed previously the US right to use into World War II. In 1942 the aptitude was converted for use as the Leupp Isolation Center, designed to stop Japanese and Japanese-American internees from the several larger internment camps time-honored by the War Relocation Authority to hold citizens and immigrants from the West Coast. They were sent here if characterized as troublemakers; some were men exasperating to regain their rights as American citizens.

The Navajo and their ancestors occupied this Place for thousands of years. In 1868 they were goaded by the United States to inherit to a reservation, which was within the New Mexico Territory until 1912. After Arizona and New Mexico were admitted as states, the reservation extended across their common border.

In 1902, the Bureau of Indian Affairs expected an Indian boarding researcher in Leupp, to support Navajo and new Native American children in the large region. The population was momentum out too far away for most children to be clever to commute to the school, so they lived as boarders at the BIA school. Soon afterward, the learned was moved to a extra location known as Old Leupp. Old Leupp is a few miles to the southeast of Leupp.