The San Luis Valley in south-central Colorado spans approximately 8,000 square miles of high desert plateau, sitting at an elevation of around 7,500 feet between the Sangre de Cristo and San Juan mountain ranges. This remote agricultural region became internationally known in the 1970s as a hotspot for unexplained cattle mutilation incidents, with the valley reporting dozens of cases involving livestock found dead under mysterious circumstances. The area's isolation, clear skies, and vast open spaces have made it a focal point for both researchers and theorists investigating unexplained phenomena. Today, visitors to the valley encounter a landscape of ranches, farms, and small communities, with the town of San Luis serving as one of the oldest settlements in Colorado.
Town of San Luis founded as one of Colorado's first permanent settlements
First documented cattle mutilation cases reported in the San Luis Valley
CBS News journalist Linda Moulton Howe conducts investigation of mutilation cases
Continued reports of unexplained livestock deaths and UFO sightings in the valley
“Here was a black and white steer and it was lying perfectly, like it should get up. There's no violence. But there was a perfect circle around that left eye that's up. The hide had been removed just down to the bone.”
“We flew do to San Luis, Colorado, because I had gotten a phone call from a sheriff there and he's telling me, 'You need to see this.'”
The San Luis Valley's significance lies not in ancient archaeological remains, but in its role as a modern mystery that has attracted scientific investigation for over four decades. The area became prominent in unexplained phenomena research following a series of cattle mutilation reports that began in the late 1970s, with animals found dead under circumstances that defied conventional explanation.
Journalist Linda Moulton Howe's 1979 CBS News investigation brought national attention to the valley's cases, documenting incidents where cattle were discovered with precise surgical incisions, missing organs, and an apparent absence of blood at the scene. Her work established the San Luis Valley as one of the most thoroughly documented regions for such phenomena, with law enforcement, veterinarians, and researchers attempting to determine causes ranging from natural predation to human activity.
Scientific analysis of the reported cases has yielded mixed results, with some researchers proposing explanations involving natural decomposition processes, predator activity, or human intervention, while others maintain that certain aspects of the cases remain genuinely unexplained. The remote location and challenging investigation conditions have made definitive conclusions difficult to reach.
What remains genuinely unknown is the exact cause of the most puzzling cases, where conventional explanations appear insufficient to account for all observed evidence. The valley continues to generate reports and attract researchers, making it an ongoing subject of investigation rather than a resolved mystery.
The San Luis Valley sits at approximately 7,500 feet elevation, making it one of the largest high-altitude valleys in the world
Linda Moulton Howe's 1979 CBS investigation won an Emmy Award for its documentation of the unexplained cattle cases
The valley's clear, dark skies have made it a popular location for both UFO watchers and legitimate astronomical observation
San Luis is recognized as Colorado's oldest town, founded in 1851 by Hispanic settlers from New Mexico
The San Luis Valley is generally accessible to visitors via highways US 160 and US 285, though many of the specific incident locations are on private ranch land. The town of San Luis offers basic amenities and serves as a base for exploring the broader valley region.
Alamosa, Colorado, approximately 20 miles northeast
Late spring through early fall provides the most comfortable weather conditions, as the high-altitude valley can experience harsh winters with heavy snow.
Roswell
Both locations are central to modern UFO phenomena and unexplained incident investigations in the United States
White Sands Proving Ground
This military testing facility represents the intersection of advanced technology and unexplained aerial phenomena
GIMBAL UAP Incident Site (Atlantic Coast of Florida)
Another modern site where unexplained phenomena have been documented and investigated by official channels