Challis Field Office

Big Lost River Access Trail

Access Map | Learn about the Big Lost River's Mountain Whitefish

The hiking areas within the Challis Field Office are dispersed and unmarked. Adventurous visitors are encouraged to explore the approximately 250 miles of open routes available in the mountains of the Mackay/Lost River Valley area. This area includes hikes to view spectacular vistas from 9 of the 11 highest peaks in Idaho.

This loop trail system includes a 3/4-mile trail designed for maximum accessibility (grade and slope) from the trailhead down to the Big Lost River.  For those wanting a more arduous hike and a spectacular view of Mt. Caleb, a side trail, also 3/4-mile hike, provides the second half of the loop. 

The trail started as a joint effort between the City of Mackay and the Bureau of Land Management. BLM staff roughed out the trail in 2006 and volunteers later refined the trail system in 2007. A Recreational Trails Program grant from the Idaho Department of Parks and Recreation helped to finish the trail system in 2008.

Remember that this trail has been a community effort. Respect the adjacent private property by staying on the trail and using non-motorized means to get to the river.

For motorized recreationists, the old road from here up Blaze Canyon to the Windy Devil communication tower is a designated ATV trail.

Location: Approximately 1 mile northwest of Mackay, Idaho along the Big Lost River. Northwest of the River Park Golf Course in Mackay. Head due west off of Beverland Road.

The Mountain Whitefish

There is a unique population of mountain whitefish in the Big Lost River which have shown a decline in relation to historical numbers and range due to a number of factors.  Federal and state government agencies, irrigation districts, conservation organizations and private land owners are all working together to reverse this trend. 

Releasing the fish you catch can help sustain and build the population of wild fish. Just remember to do as little damage as possible by keeping the fish in the water as much as you can, de-hooking quickly and efficiently, and minimize handling of the fish.

Do your part by practicing catch and release fishing techniques:

  • Decide beforehand which fish are to be kept and immediately release all others.
  • Try fishing with barbless hooks or flatten the barb on the hook.
  • Wet your hands or gloves to handle the fish and minimize the time the fish is out of the water.
  • Use either needle-nose pliers or a de-hooking tool to gently remove the hook from the fish’s mouth by backing the hook out through the original injury.
  • If the fish has swallowed the hook, or if the hook is set too deeply, cut the line and release the fish.  The hook will dissolve over time with no harm to the fish.
  • Once the hook is removed or the line is cut, gently hold the fish in the water, pointing
    upstream, until it can swim away on its own.
  • If the hook is in the gills, the throat, or an artery, the fish’s chances of survival are greatly reduced. If it’s legal, keep the fish. Also, if a fish is bleeding, keep it if it’s legal to do so.

fishing hooks with and without barbs


Lake Creek Trail

Big Lost Access Trail

Big Lost River Access Trail view of Mt. McCaleb