[14] The Global Volcanism Program reports that the field includes somewhere between 32 and 50 shield volcanoes and cinder cones, with many vents concentrated northwest of the town of Boring.

[16] It marks one of five volcanic fields along the Quaternary Cascade arc, along with Indian Heaven, Tumalo in Oregon, the Mount Bachelor chain, and Caribou in California.

[14] The Boring Lava Field has erupted material derived from hot mantle magma, and the subducting Juan de Fuca plate may be as shallow as 50 miles (80 km) in depth at their location.

[6] Like many other vents in the Boring Lava Field, Rocky Butte consists of basaltic andesite with olivine phenocrysts, and it has a calc-alkalic composition.

[23] Vug cavities were identified from rock in the historic quarry on the eastern side of Rocky Butte by scientists from the United States Geological Survey, including optically positive hornblende (also known as pargasite) with a pale brown color.

[24] The hill descends to meet the floodplain of the Columbia River, and at lower elevations, the mountain has cliffs on its northern and eastern sides.

[5] At the foot of Rocky Butte, there is a fosse (a ditch), which extends for 1 mile (1.6 km) before it opens toward the Columbia River to the north and divides to the south into two arms that run west and southwest.

[26] These features are likely the product of more than just erosional forces; Bretz (1925) argued that the fosse resulted from fluid eddies that pushed downward where currents interacted with the eastern side of Rocky Butte, and the terrace formed from accumulation of deposits in water under the blockage.

[23] There is a magnetic anomaly about 2.5 miles (4 km) northwest from Rocky Butte in Portland, but it is unlikely to be associated with the volcano or the Boring Lava Field in general.

[24] The moderate climate and ample precipitation of the region lead to rapid regrowth of vegetation on untended sites, which can hamper fieldwork in the area.

[31] These cleared and burned land plots sustain rich stands of secondary forest, featuring gorse, huckleberry, nettles, poison oak, salal, and blackberry.

Forests support stands of Douglas fir, western hemlock, western redcedar, Pacific dogwood, bigleaf maple, Oregon ash, red alder, cascara buckthorn, Pacific madrone, and Oregon white oak; within swamps and moist areas in creeks, the shrub Devil's club can be observed.

[31] The Riparian zones in the Lava Field area host diverse species, and they are influenced by uplands that serve as migration connections for birds, mammals, reptiles, and some amphibians.

[35] Among plant species, they determined the following species to be sensitive: white top aster, golden Indian paintbrush, tall bugbane, pale larkspur, peacock larkspur, Willamette daisy, water howellia, Bradshaw's lomatium, Kincaid's lupine, Howell's montia, Nelson's checkermallow, and Oregon sullivantia.

[39] Rock from Rocky Butte's eastern slopes was used for the Multnomah County jail building,[6] and some were later used for renovation of the Historic Columbia River Highway.

[23] The Rocky Butte jail, completed in 1947,[40] served as the major facility for male prisoners in Multnomah County, with a courtyard and recreation field.

[40] According to Rubin (1973), the Rocky Butte jail housed 320 inmates,[41] but Houston, Gibbons, and Jones (1988) claimed that it often exceeded this limit.

[42] In general, the jail was known for being the subject of multiple grand jury investigations for security concerns, dirty conditions, access to drugs, violence, lack of organized programming, and most notably, during the 1960s and 1970s for severe overcrowding.

[40] Further attempts to replace the Rocky Butte jail were motivated by a successful escape in 1981 and a gun smuggling incident that resulted in an officer being shot in 1982.

[40] The Multnomah County Detention Center (MCDC) was built in downtown Portland after Rocky Butte Jail was demolished in 1984 to make way for Interstate 205.

The project took 16 months to complete, and workers used hand mining and drill and shoot methods to excavate layers of cinders and lava flows.

Ran by its founder, Joseph Wood Hill, it closed in 1959 after its enrollment had declined significantly,[53] and the school was purchased by Judson Baptist College.

[54] Today, Portland Bible College has a campus on Rocky Butte[55] with offices and dormitory buildings,[54] and The Grotto, a famous Catholic shrine encompassing 62 acres (0.25 km2), lies adjacent to the volcano.

On the upper level of the shrine is the Chapel of St. Anne, which sits on the northern side of Rocky Butte and offers views of the Columbia River and Mount St. Helens.

[57] In 2000, Portland Police Bureau Officer Mark Kruger placed a shrine to Nazi soldiers on public park property at Rocky Butte.

[58][59][60][61][62] In May 2018, government officials from the Oregon Department of Transportation began clearing belongings and debris from a long-standing homeless campsite at the eastern side of Rocky Butte, also posting eviction notices.

There are a number of climber and biker trails made by civilians on the base and lower parts of the mountain, as well as climbing paths near the summit, which are unfenced and can be unsafe.

[74] Rocky Butte provides a variety of climbs including cracks, dihedrals, slab, vertical, and overhanging face routes.