The route was established in 1991. It is the highest numbered route in the Arizona state highway system. The number 989 was initially assigned as part of a proposed highway network for the
Tucson area (in this case, the Tangerine Highway) that was never implemented. No signage has ever existed for this highway. According to ADOT Spokesperson Donal Cassano, "SR 989 was turned back to Oro Valley (as of June 2012) and is no longer a state highway." Nonetheless, the
Arizona Department of Transportation (ADOT) continues to log the highway in its official state highway system. ==History==