Boulder, CO: Mount Sanitas Loop

At first glance, the 6,863-foot summit of Mount Sanitas may seem modest compared to the 8,000-foot peaks dotting the ridgeline west of Boulder, but this 3.4-mile hike (or trail run) packs plenty of punch for a short outing.

Start at the west end of Mapleton Avenue and hike northwest along a brief, 0.2-mile flat stretch up the Sanitas Valley Trail. From here, you’ll navigate a steep obstacle course of log steps, rock slabs, and giant boulders (and climb 1,100 feet in one mile) past overlooks of both the foothills and mountain canyons to the west. At Sanitas’ small summit, take in expansive views of Boulder and the eastern plains before tackling an equally steep and rocky descent of the mountain’s eastern slopes. Two miles into the hike, the route merges onto the Dakota Ridge Trail for an easy walk back to Mapleton Avenue.

-Mapped by Kim Phillips

Trail Facts

• Distance: 5.5

Waypoints

SAN001

Location: 40.0206298828125, -105.29167175293

Walk west along Mapleton Avenue for roughly 750 feet to the Mount Sanitas Trailhead on the right side of the road.

SAN002

Location: 40.0207748413086, -105.294143676758

Leave the sidewalk and bear right onto the marked Mount Sanitas Valley Trail. Walk northwest on wide, dirt path.

SAN003

Location: 40.0212326049805, -105.29524230957

Continue straight @ signed 4-way junction onto the Mount Sanitas Trail (Mount Sanitas Valley Trail veers to the right). Ahead, trail cuts through a grassy field punctuated with rocky outcroppings.

SAN004

Location: 40.0214729309082, -105.295860290527

Keep straight @ 4-way.

SAN005

Location: 40.0215759277344, -105.296569824219

Climb up several log steps shaded by trees, then cross a short wooden footbridge. Ahead, the trail winds to the west through open pine forest.

SAN006

Location: 40.0214157104492, -105.29761505127

The steep, rocky ascent begins. Tackle a series of log and rock steps that climb up the ridgeline.

SAN007

Location: 40.0223007202148, -105.298095703125

Pass a popular bouldering site on the right. Continue climbing north.

SAN008

Location: 40.022834777832, -105.298561096191

Pass another climbing access on right. Giant sandstone outcrops flank the trail on the right.

SAN009

Location: 40.023738861084, -105.298698425293

Continue steep climb up ridge.

SAN010

Location: 40.0256271362305, -105.299797058105

The trail skirts a massive boulder on the left. Stand on top of this rock overlook for views into Sunshine Canyon to the west.

SAN011

Location: 40.0266990661621, -105.300285339355

This ridgeline vantage point offers expansive views east across Boulder.

SAN012

Location: 40.0279388427734, -105.301376342773

Climb steep rock steps; vibrant wildflowers pepper the grassy slopes that border the trail to the east.

SAN013

Location: 40.0288734436035, -105.302352905273

Squeeze through a narrow gap in boulders that block the trail, then climb northwest up rock slabs dotted with seasonal wildflowers.

SAN014

Location: 40.0298080444336, -105.303062438965

Trail briefly curves around the west side of the mountain. Continue hiking northwest up ridge.

SAN015

Location: 40.0331993103027, -105.305114746094

The final 500-foot stretch to the summit travels up another set of rock steps; pine trees flank the trail.

SAN016

Location: 40.0344009399414, -105.305297851562

Mount Sanitas (6,863 ft.): A metal rod marks this small, rocky summit. Rest your legs while taking in the expansive views of Boulder and the eastern plains. Next: Begin the steep and rocky descent of Sanitas’ eastern slopes.

SAN017

Location: 40.0346870422363, -105.304359436035

Terrain levels out for next 0.1 mile. Ahead, trail switchbacks to the right, heading southeast.

SAN018

Location: 40.0345687866211, -105.303764343262

Travel beneath a gigantic boulder that towers over the trail. Next, the trail cuts between two tightly-spaced boulders (follow the small trail signs attached to a fallen log).

SAN019

Location: 40.034610748291, -105.301048278809

Trail cuts to the right, heading south.

SAN020

Location: 40.0343208312988, -105.300315856934

Bear left @ 3-way. Trail descends to the north.

SAN021

Location: 40.0349502563477, -105.297370910645

Bear left @ Y-junction onto the Dakota Ridge Trail (Sanitas Valley Trail forks to the right down the drainage). Hike south along rolling ridgeline.

SAN022

Location: 40.0324440002441, -105.296562194824

Continue heading south on gentle trail. Views extend across grassy, pine-dotted hillsides to The Flatirons.

SAN023

Location: 40.0275115966797, -105.296142578125

Keep straight @ 3-way.

SAN024

Location: 40.0250396728516, -105.29615020752

Turn left @ T-junction.

SAN025

Location: 40.0234031677246, -105.295188903809

Turn right @ T-junction for gentle descent to the Sanitas Valley Trail.

SAN026

Location: 40.0236740112305, -105.296195983887

Turn left @ T-junction onto the Sanitas Valley Trail. Head south to Waypoint 3, then turn left and retrace steps to trailhead.

Mount Sanitas Trailhead

Location: 40.0207824707031, -105.29411315918

First Trail Junction

Location: 40.021240234375, -105.295257568359

Continue straight on Mount Sanitas Trail.

Rock Outcrops

Location: 40.0213661193848, -105.295593261719

Log Steps

Location: 40.0215644836426, -105.296501159668

Trail Views

Location: 40.0215301513672, -105.296859741211

Open Woods

Location: 40.0214614868164, -105.297149658203

Steep Steps

Location: 40.0214042663574, -105.297607421875

Climbing Access

Location: 40.0228233337402, -105.298545837402

Rocky Overlook

Location: 40.0256500244141, -105.299797058105

Wildflowers

Location: 40.0259170532227, -105.299873352051

Wildflowers

Location: 40.0263137817383, -105.300003051758

Views to the Southwest

Location: 40.0265007019043, -105.300155639648

Views of Boulder

Location: 40.0266990661621, -105.300285339355

Wildflowers

Location: 40.0275115966797, -105.301063537598

Rocky Ascent

Location: 40.0279197692871, -105.30135345459

Views to the South

Location: 40.0283851623535, -105.301948547363

Rocky Terrain

Location: 40.0290946960449, -105.302612304688

Wildflowers punctuate the rocky terrain.

Summit Views

Location: 40.0343780517578, -105.305252075195

Views stretch across Boulder from the summit of Mount Sanitas.

Trailside Boulder

Location: 40.0345764160156, -105.303749084473

Trail Sign

Location: 40.0345306396484, -105.303298950195

Views to the West

Location: 40.0358352661133, -105.298980712891

Dakota Ridge Trail Junction

Location: 40.0349617004394, -105.297370910645

Views from Dakota Ridge Trail

Location: 40.0324363708496, -105.29655456543

Dakota Ridge Trail

Location: 40.0303649902344, -105.29630279541