Lost Trail Pass is a mountain pass in Lemhi County, Idaho at about 2,140 m (7,021 ft) above sea level. It sits roughly 58 km (36 mi) N of Salmon.
Lost Trail Pass is a mountain pass in the Rocky Mountains of the northwestern United States, on the border of Idaho and Montana in the Bitterroot Mountains. The pass is at an elevation of 7,014 feet (2,138 m) above sea level and is traversed by U.S. Highway 93. The pass is about a half mile (1 km) west of the Continental Divide, which retreats eastward at this point, inside Montana along the Ravalli–Beaverhead County border, toward Butte. Southeast of Lost Trail Pass, the divide straddles the state line into Yellowstone National Park and continues in Wyoming. South of the pass in Idaho is the north fork of the Salmon River, which descends with US 93 to North Fork to join the main Salmon River. In Montana, US 93 drops northward into the Bitterroot River Valley and gradually descends toward Hamilton, Lolo, and Missoula.From the Wikipedia article “Lost Trail Pass”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Lost Trail Pass the sunrise point swings a long way through the year: about 54° (NE) at the June solstice and 124° (SE) in late December. Sunset moves from 306° (NW) in June to 236° (WSW) in December, and the midday sun climbs to 68° in summer but only 21° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:40 AM | 89° E | 7:48 PM | 271° W | 44° | 12h 09m |
| June solstice (Jun 21) | 5:47 AM | 54° NE | 9:30 PM | 306° NW | 68° | 15h 43m |
| September equinox (Sep 22) | 7:24 AM | 89° E | 7:35 PM | 271° W | 45° | 12h 12m |
| December solstice (Dec 21) | 8:14 AM | 124° SE | 4:55 PM | 236° WSW | 21° | 8h 41m |
Azimuth is measured clockwise from true north (90° = east, 270° = west). Computed for 2026; values change by less than a degree from year to year.
Golden hour & blue hour by month
Mountain passes sit above valleys, so they reward sunrise and sunset with layered ridges, valley fog and long shadows.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 7:40 AM | 8:13 AM | 9:01 AM | 4:31 PM | 5:18 PM | 5:52 PM | 9h 05m |
| February | 7:08 AM | 7:39 AM | 8:21 AM | 5:21 PM | 6:03 PM | 6:33 PM | 10h 24m |
| March | 7:20 AM | 7:49 AM | 8:29 AM | 7:03 PM | 7:42 PM | 8:11 PM | 11h 53m |
| April | 6:20 AM | 6:51 AM | 7:31 AM | 7:42 PM | 8:22 PM | 8:53 PM | 13h 32m |
| May | 5:31 AM | 6:05 AM | 6:49 AM | 8:17 PM | 9:01 PM | 9:35 PM | 14h 55m |
| June | 5:08 AM | 5:47 AM | 6:32 AM | 8:42 PM | 9:28 PM | 10:06 PM | 15h 41m |
| July | 5:25 AM | 6:02 AM | 6:46 AM | 8:39 PM | 9:23 PM | 10:00 PM | 15h 22m |
| August | 6:04 AM | 6:37 AM | 7:18 AM | 8:04 PM | 8:45 PM | 9:18 PM | 14h 09m |
| September | 6:45 AM | 7:15 AM | 7:54 AM | 7:10 PM | 7:49 PM | 8:19 PM | 12h 34m |
| October | 7:23 AM | 7:53 AM | 8:33 AM | 6:11 PM | 6:52 PM | 7:21 PM | 10h 59m |
| November | 7:04 AM | 7:36 AM | 8:22 AM | 4:21 PM | 5:06 PM | 5:39 PM | 9h 30m |
| December | 7:36 AM | 8:11 AM | 9:00 AM | 4:03 PM | 4:53 PM | 5:27 PM | 8h 42m |
Local time (America/Denver), including daylight saving time. Golden hour runs from about −4° to +6° solar altitude, so the morning golden hour begins during blue hour, before sunrise.
Milky Way & night sky
From Lost Trail Pass, the Milky Way core is visible in a dark sky from April through August. June gives the longest window (about 2.8 hours on a moonless night), and the core peaks around 15° above the southern horizon. Our light-pollution model puts the sky at about Bortle 1 (excellent dark-sky site), which is excellent for astrophotography.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -4° | — |
| February | Below 10° in darkness | — | 7° | — |
| March | 5:42 AM – 6:02 AM | 0.3 | 12° | SSE → SSE |
| April | 3:42 AM – 4:52 AM | 1.2 | 14° | SSE → SSE |
| May | 1:43 AM – 3:43 AM | 2.0 | 15° | SSE → S |
| June | 12:08 AM – 2:58 AM | 2.8 | 15° | SSE → SSW |
| July | 11:49 PM – 1:49 AM | 2.0 | 15° | S → SSW |
| August | 10:43 PM – 11:43 PM | 1.0 | 14° | SSW → SSW |
| September | 9:31 PM – 9:41 PM | 0.2 | 11° | SSW → SSW |
| October | Below 10° in darkness | — | 6° | — |
| November | Below 10° in darkness | — | -3° | — |
| December | Below 10° in darkness | — | -20° | — |
Window when the galactic core is at least 10° high during astronomical darkness on the 15th of each month. Pick nights within a few days of the new moon. Plan exact nights with the Milky Way planner.
Estimated sky darkness: 1 Bortle 1 — Excellent dark-sky site. The Milky Way casts faint shadows; zodiacal light and airglow are obvious. Modeled zenith brightness ≈ 21.94 mag/arcsec². Aurora needs roughly Kp 5.0+ to show low on the northern horizon here.
Weather & best season
Long-term NASA satellite data for this area show July as the clearest month (about 36% average cloud cover) and March as the cloudiest (71%). July is the warmest month and January the coldest, which matters for gear, snow access and how long batteries last at night.
Average cloud cover (%)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High °F | 40 | 46 | 61 | 71 | 83 | 88 | 97 | 92 | 87 | 77 | 62 | 41 |
| Low °F | -30 | -31 | -17 | 0 | 13 | 22 | 31 | 30 | 20 | -4 | -21 | -25 |
| Precip. (in) | 2.2 | 2.2 | 2.2 | 2.3 | 2.6 | 2.8 | 1.0 | 1.2 | 1.6 | 1.7 | 2.0 | 2.3 |
Monthly climatology for the surrounding 1° grid cell from NASA POWER (MERRA-2). Mountain sites can be colder and cloudier than the cell average.
Photography tips for this mountain pass
- Check road status before driving: many high passes close seasonally or after storms.
- Look for the road itself as a leading line — switchbacks from above make strong compositions.
- Weather changes fast at elevation; carry layers even in summer.
- Summit pull-outs often face one direction; use the sun azimuth table to see whether sunrise or sunset suits the view.
- Scout in daylight if you plan to shoot at night or before sunrise.
Season: Summer and early autumn are the main season; winter visits depend on plowing and avalanche conditions.
Suggested gear: Telephoto lens, Tripod, Warm layers, Road-condition app. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Lost Trail Pass, closest first.
Mountain Pass
Mountain Pass
Waterfall
Fire Lookout
Mountain PassCampgrounds nearby (Recreation.gov)
- Gordon Reese Cabin1.1 km (0.7 mi) · reservable
- Hogan Cabin5.8 km (3.6 mi) · reservable
- Indian Trees Campground7.0 km (4.3 mi) · reservable
- Twin Creek Campground Group Camping Site9.6 km (6.0 mi) · reservable
- Twogood Cabin10.4 km (6.4 mi) · reservable
FAQ
When is the best time to photograph Lost Trail Pass?
What time is golden hour at Lost Trail Pass?
Where does the sun rise and set at Lost Trail Pass?
Can you see the Milky Way from Lost Trail Pass?
Do you need a permit to photograph at Lost Trail Pass?
How far is Lost Trail Pass from Salmon?
Sources
Location data: Wikidata, USGS GNIS / GeoNames, Wikipedia. Sun, moon and Milky Way times are computed by LWPhoto Atlas for 2026. Climate: NASA POWER. Sky darkness is a population-based estimate (Walker's law), not a measurement. See data sources & licenses.