AMBLEWAY Wildest hikes

Boulder Reservoir–Sixmile Reservoir, 10 sights

12.1 mi · ▲ 223 ft · 4 hr 9 min

Boulder Reservoir–Sixmile Reservoir, 10 sights is a 12.1-mile out-and-back near Niwot, CO. The route passes Boulder Reservoir and Humpty Hump Viewpoint before reaching Sixmile Reservoir at the turnaround, 6 miles in. It is mostly level, with 223 ft of elevation gain, and mostly gravel. It scores 0/100 on the Ambleway Wildness scale: paved and peopled.

Elevation

0 mi5,109 – 5,220 ft13.6 mi

Getting there

Trailhead: Unnamed 40.10485, -105.14514
Nearest town Niwot, CO
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Directions

AMBLEWAYwww.ambleway.com

Boulder Reservoir–Sixmile Reservoir, 10 sights

12.1 mi · ▲ 223 ft · 4 hr 9 min

Elevation 5,107–5,221 ft

Out & Back

Trailhead: 40.10485, -105.14514

Weather Sep 4: sunrise 6:32 AM · sunset 7:29 PM

Toilets at the trailhead · Parking lot at the trailhead

  1. Start at the trailhead, heading N.
  2. 100 ftTurn left onto Cougar Trail, heading SW.
  3. 0.4 miSharp right onto Niwot Loop Trail, heading W.
  4. 0.4 miTurn right onto Hidden Star Trail, heading S.
  5. 150 ftBear left, heading W.
  6. 0.1 miBear left, heading NW.
  7. 350 ftTurn left, heading SW.
  8. 0.1 miTurn right, heading S.
  9. 0.7 miTurn right onto Niwot Loop Trail, heading E.
  10. 0.1 miBear right, heading W.
  11. 50 ftTurn left, heading W.
  12. 0.2 miBear left onto Niwot Loop, heading SW.
  13. 50 ftContinue straight onto Longmont-to-Boulder (LOBO) Regional Trail, heading SW.
  14. 1.9 miTurn right onto IBM Connector Trail, heading W.
  15. 0.8 miPass Boulder Reservoir.
  16. 50 ftTurn left, heading NW.
  17. 0.2 miTurn left, heading NW.
  18. 50 ftBear left onto Boulder Reservoir Dam (North), heading NW.
  19. 0.3 miPass Humpty Hump Viewpoint.
  20. 0.2 miTurn left onto Humpty Hump, heading S.
  21. 250 ftContinue straight onto Boulder Reservoir Dam (South), heading S.
  22. 0.4 miPass Sixmile Reservoir.
  23. 0.3 miReach Boulder Reservoir, then turn around and head back the way you came.
  24. 0.7 miContinue straight onto Humpty Hump, heading NE.
  25. 250 ftTurn right, heading NE.
  26. 50 ftContinue straight onto Boulder Reservoir Dam (North), heading NE.
  27. 0.5 miBear right, heading N.
  28. 50 ftTurn right, heading N.
  29. 0.2 miTurn right onto IBM Connector Trail, heading NE.
  30. 0.8 miTurn left onto Longmont-to-Boulder (LOBO) Regional Trail, heading SE.
  31. 1.9 miContinue straight onto Niwot Loop, heading E.
  32. 50 ftBear right onto Niwot Loop Trail, heading E.
  33. 0.2 miTurn left, heading NE.
  34. 50 ftTurn right, heading NE.
  35. 0.1 miTurn left onto Hidden Star Trail, heading NE.
  36. 0.6 miTurn right, heading NE.
  37. 0.1 miTurn left, heading NE.
  38. 0.1 miTurn left, heading NE.
  39. 250 ftBear right, heading NW.
  40. 400 ftTurn left, heading W.
  41. 350 ftTurn left onto Niwot Loop Trail, heading NE.
  42. 0.4 miSharp left onto Cougar Trail, heading N.
  43. 0.4 miTurn right, heading E.
  44. 50 ftArrive back at the trailhead.

Each distance is the walk from the previous step. Tap a step for a map of its junction.

Trail map, photos and weather for this hike: www.ambleway.com/hikes/boulder-reservoir-sixmile-reservoir-out-back-10-sights

Trail surface

71% gravel16% dirt11% paved2% unspecified

Weather

Sunrise 6:32 AMSunset 7:29 PM

Sunset

The best sunset spot on this hike is 0.1 mi in (~2 min). Leave by 7:08 PM for the 7:29 PM sunset. Back at your car by 7:46 PM — 11 min before dark.

More sunset hikes nearby

Good to know

  • Toilets at the trailhead
  • Parking lot at the trailhead

Hikes near Niwot, Colorado