Monster Tower, Summit in San Juan County, United States.

Monster Tower is a 600-foot-tall (180 m) sandstone tower in the Island in the Sky District of Canyonlands National Park, San Juan County, Utah. It stands 300 feet southeast of Washer Woman, a towering arch nearly as high; the two form an eroded fin of Wingate Sandstone, lithified wind-blown dunes deposited about 200 million years ago in the Late Triassic. The top rises 1,400 feet above the White Rim Road in roughly one mile.

Monster Tower's recorded history is one of climbing rather than settlement. Layton Kor, Larry Dalke and Cub Schaefer made the first ascent in December 1963 via the South Ridge, rated class 5.11. Ken Trout and Kirk Miller opened the North Ridge (5.11a) in 1981, and Edward Webster and Chester Dreiman climbed Monster of Rock (5.11) on the south face in 1982. The tower later lay within Canyonlands National Park, established in 1964.

The name Washer Woman, given to the arch 300 feet northwest of Monster Tower, comes from its shape: a woman bent over a washtub. Monster Tower and Washer Woman form one eroded fin of Wingate Sandstone, dunes deposited about 200 million years ago in the Late Triassic. Climbers know the tower through routes such as the South Ridge, first climbed in December 1963 by Layton Kor, Larry Dalke and Cub Schaefer.

The easiest view of Monster Tower is from the short hike to Mesa Arch, 1.5 mi (2.4 km) west. Reaching the tower itself requires the four-wheel-drive White Rim Road; from there its top rises 1,400 feet above the road in about one mile. Spring and fall are the most favorable seasons, as the desert receives under 10 inches of rain a year.

Monster Tower's first ascent was made in December 1963 by Layton Kor, Larry Dalke and Cub Schaefer via the South Ridge, rated class 5.11. The North Ridge, first climbed in 1981 by Ken Trout and Kirk Miller, is considered the best route on the tower at class 5.11a. Los Banditos is an aid climb on the formation.