Belknap is not forested and most of its lava flows are not vegetated, though there is some wildlife in the area around the volcano, as well as a number of tree molds formed by its eruptive activity.

The Oregon Skyline Trail, which runs to the west of Belknap's lava flows, follows paths used by Native American populations, who harvested huckleberries in the area.

[5] According to Hildreth (2007), Belknap Crater is a broad, low-angled shield volcano compared to other mafic (rich in magnesium and iron) volcanic cones.

[9] Oregon Route 242, which follows the course of the McKenzie River, passes through the lava fields produced by Belknap Crater, the Yapoah cinder cone volcano, and a number of other volcanic vents.

There are at least 466 Quaternary volcanoes in the Sisters Reach, including several aligned segments of volcanic vents and rare eruptive units of rhyolite (uncommon elsewhere in the Cascade arc).

[24] The area by Belknap and Mount Bachelor is marked by extensional tectonics, with a high density of mafic (rich in magnesium and iron) volcanic vents.

[26] Dissolved magmatic carbon dioxide flux at Mount Washington and Belknap Crater was calculated by James et al. (1999) to be 5.3 pounds (2.4 kg) per year.

It marks an intermediate scale between cinder cones that produced small lava flows such as Twin Craters or Yapoah and larger volcanoes like Mount Washington or Three Fingered Jack.

[42] There may have been a large lava field in the glacier valley north of the Twin Craters cone, but any evidence is now buried under the Belknap shield.

[43] Deposits from Belknap buried older lava flows from the Sand Mountain Volcanic Field[44] as well as a series of four cinder cones located about 3.5 miles (5.6 km) to the southwest of Mount Washington.

[46] The hot springs are indicative of a fault that underlies the Cascade Volcanoes, onto which the east side dropped down and lava intrusions formed volcanic centers.

[47] Eruptions at Belknap Crater built up the main shield volcano over repeated activity from vents surrounding a composite summit cone.

[6] According to the Global Volcanism Program, Belknap Crater had four Holocene eruptive periods confirmed by geological evidence including corrected radiocarbon dating and magnetism; their durations are not known.

[12][48] Belknap's oldest exposed lava deposits are located on the eastern flanks of the volcano, produced by vents that may have been buried by later activity.

They coursed mostly to the northeast and split into two lobes on both sides of the Dugout Butte ridge, extending about 7 miles (11 km) from their source vent,[8] along the eastern edges of the Deschutes National Forest.

Belknap Crater's lava flows were produced from its northeastern base and extended 9.3 miles (15 km) to the west, reaching the McKenzie River valley.

These events represent one of the largest periods of recent volcanism in the Cascade Range,[3] and were comparable in terms of effusion rates to the formation of Mount Bachelor.

[50] The initial eruptions generated tephra, which covered an extensive area to the northeast and southeast, as well as basaltic lava flows that extended 6 miles (9.7 km) from the burgeoning shield volcano edifice[2] to the east.

[2] According to Sherrod et al. (2004), lava from Little Belknap formed a tree mold in the southern part of the Sand Mountain volcanic field, which was dated to 2,883 ± 175 years Before Present (B.P.)

[48] Sherrod et al. (2004) also describe charcoal detected under a lava flow that coursed down Belknap Crater's western flank, which yielded two radiocarbon dating ages: 1,590 ± 160 years B.P.

[51] A third eruptive period constructed the bulk of the volcanic complex[28] with basaltic andesite lava from Belknap Crater's central vent about 1,500 years ago.

is more accurate because the deposit contains concentrated amounts of the cosmogenic nuclide isotope 3He, which would require a longer surface exposure than Taylor's calculation would allow,[48] at least 2,000 years B.P.

[12] A final eruptive phase produced lava flows that extended 9 miles (14 km) to the west into the McKenzie River valley,[2] also coursing to the north and south.

[17] In total, the Belknap shield and its multiple vents were formed in less than 1,500 years, which was a comparable effusion rate to the Nash Crater scoria cone, the Sand Mountain Volcanic Field, and the Mount Bachelor chain.

Moreover, low-volume lahars from eruptions would likely enter the McKenzie River valley, which is broad and fairly gently sloped, where they might move downstream through flood plains or small channels.

[4] During the days of the American pioneer, the Santiam and McKenzie passes were the two major routes through the Deschutes Forest area, eventually transforming into highways for Oregon's interior.

[60] The Oregon Skyline Trail, which runs to the west of Belknap's lava flows, follows paths used by Native American populations, who harvested huckleberries in the area.

The round trip from intersection of the Pacific Crest Trail and Oregon Route 242 to Little Belknap Crater is about 5.6 miles (9.0 km) and ranges in elevation from 5,350 to 6,250 feet (1,630 to 1,900 m), with an easy to moderate difficulty level.

[61] The round trip to Belknap Crater is about 6.8 miles (10.9 km) from the trailhead and is more difficult owing to the steep climb to the summit on fine cinders.

[65] The Oregon Skyline Trail, part of which runs for 38 miles (61 km) through the Deschutes National Forest, passes westward of the Belknap lava fields.