Distance: 2.5 miles (one way)
Best time of year: Spring, Summer, Fall
Last hiked: 2015 September
Lone Star Geyser is a popular hike for many different reasons. It’s a unique geyser located slightly off the beaten path, it has a massive cone at its base, it’s one of the most punctual large geysers in the park, it’s accessible for bicycles, and it’s a very easy hike, making it accessible for nearly anyone.
Over the course of 2.5 miles, the trail very gradually ascends a mere 50-60 feet in elevation as it meanders along the Firehole River. The trail crosses the river early in the hike and subsequently pops in and out of meadows along the way, breaking up the forest cover from time to time.
At 2.5 miles, a small natural barricade prevents bikes from proceeding any further, and just beyond is Lone Star Geyser. The geyser erupts every three hours, nearly on the dot. Information on its predicted eruption times can be obtained from the Old Faithful Visitor Center, or others along the trail if you want to chance it, or have the time to spare. Eruptions can shoot as high as 40 feet and the cone itself is over 10 feet high! Keep in mind that on average, cones are built up from the "siliceous sinter" in the water 1/2 to 1 full inch each century. That makes it an extremely old cone geyser!
After the eruption, stick around for a while. Once the main water eruption occurs, the geyser enters into its steam phase eruption, rapidly ejecting huge amounts of steam into the air. It’s quite the sight to see…and hear.
From the Old Faithful Visitor Center, merge onto the main highway heading southbound. Follow the main highway south for 2.75 miles and you’ll see the Kepler Cascades turnout on the right. On the far southern end of the turnout, there will be an additional parking area loop where the trail begins.