🌤 Weather at Three Island Crossing State Park by season
| Spring | Summer | Fall | Winter |
|---|---|---|---|
| 32–78 °F | 53–99 °F | 29–86 °F | 24–50 °F |
Each range runs from the coldest monthly average low to the warmest monthly average high in that season (1991-2020 climate normals), measured at Glenns Ferry, 0 mi away, elevation 2,466 ft. Conditions at the park can differ from the station, especially where elevation differs — check a forecast before you go.
Three Island Crossing State Park is a public state park in Idaho near Glenns Ferry in Elmore County. Spanning 613 acres and established in 1971, this park offers a peaceful retreat into nature for visitors of all ages.
Quick Facts
| State | Idaho |
| Nearest City | Glenns Ferry |
| County | Elmore |
| Park Size | 613 acres |
| Established | 1971 |
| Google Rating | ⭐ 4.5/5 (600 reviews) |
Location & Getting There
Three Island Crossing State Park is located near Glenns Ferry, Idaho. The park’s coordinates are 42.9447, -115.3180.
Things to Do
Idaho state parks showcase the rugged beauty of the Northern Rockies and high desert — from alpine lakes and dramatic canyons to volcanic landscapes and whitewater rivers. Activities include hiking through mountainous terrain, swimming and boating on pristine alpine and reservoir lakes, fishing for rainbow and cutthroat trout in clear mountain waters, camping in remote forested settings, mountain biking challenging terrain, cross-country skiing in winter, whitewater rafting on renowned rivers, and exploring natural hot springs and volcanic formations.
Best Time to Visit
Summer (June–August) is peak season with warm days, open mountain trails, and excellent lake recreation. Fall (September–October) brings golden aspens and larches to the forests and fewer crowds. Spring is muddy at higher elevations but great for waterfall viewing and fishing as rivers swell. Winter transforms mountain parks into cross-country skiing and snowmobiling destinations. Northern Idaho parks have shorter seasons due to heavier snowfall.
Visitor Tips
Idaho state parks charge a vehicle entry fee ($7/day or $40/annual). Camping reservations through the Idaho State Parks reservation system up to 9 months in advance. Many parks are remote with limited cell service and amenities — come prepared. Bear country protocols apply in northern Idaho parks. Water levels on reservoir parks fluctuate significantly during drawdown seasons.
Explore More Idaho State Parks
Three Island Crossing State Park is one of many outstanding state parks in Idaho. Discover more parks in our Best State Parks in Idaho guide, or use our Park Finder to search by activity, location, or features.
Make it a road trip: Pair a visit with Glenns Ferry Historical State Park (a short drive away) or Bruneau Dunes State Park (within about an hour’s drive).
🐾 Dogs & Pets at Three Island Crossing State Park
- Pets allowed? statewide rule
- Pets are welcome in most Idaho state parks and on trails, but only if confined or controlled on a leash no longer than 6 feet.
- Leash rule statewide rule
- 6 ft maximum leash required, or pet must be confined (e.g. in a camper)
- Beaches & swim areas statewide rule
- Pets are prohibited from all swim areas and beaches statewide (service animals excepted)
- Cabins & lodging statewide rule
- Pets are allowed at most parks but some parks prohibit them in some cabins and yurts
- Statewide exceptions statewide rule
- Park managers may designate off-leash exercise areas (e.g. Eagle Island off-leash trails); pets may not be left unattended
Are dogs allowed at Three Island Crossing State Park?
Pets are welcome in most Idaho state parks and on trails, but only if confined or controlled on a leash no longer than 6 feet. Individual parks can post stricter rules — check signage on arrival.
Rules verified July 2026 via parksandrecreation.idaho.gov. More: Idaho state parks guide · Dog rules in all 50 states compared
Park Location
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