This is just a short list of, in my opinion, the Top 6 Geysers to try to take time and see erupt at least once while you are visiting Yellowstone. I initially was going to make this a list of the Top 5 but found that I could not rate Old Faithful, the best known of all of Yellowstones Geysers in the Top 5, so expanded it Top 6 so I could include Old Faithful. All these geysers are predictable to some degree and except for Eichinus Geyser, predicted eruption times are available at the Ranger Station located at the top of the Upper Geyser Basin by Old Faithful.
6. Old Faithful Geyser in the Upper Geyser Basin. Old Faithful is the most publicized Geyser in Yellowstone because it erupts so many times a day and can be predicted with a high degree of accuracy. However, it is a cone geyser whose cone is slowly being filled in and between that and changes within the ground structure of Yellowstone it is not near the sight it used to be.
5. Daisy Geyser in the Upper Geyser Basin. Daisy erupts several times a day, with a fairly short range of predictability. It is a probably around a 20 minute walk into the Upper Geyser Basin from Old Faithful. It erupts at an angle of 30 degrees off vertical and reaches heights of 70 to 80 feet.
4. Eichinus Geyser is in the Norris Geyser Basin. This Geyser erupts approximately once an hour (or maybe I should say, tries to erupt once an hour). Yellowstone National Park is a very seismic active area and the seismic activity causes the underground tubes of the geysers to change which affects how the geyser acts. Eichinus used to erupt about once an hour and its eruptions were 8 to 12 minutes in length with an occassional super eruption lasting up to around an hour. However, the last time I visited Yellowstone, seismic activity had caused changes to where around half of Eichinus' eruptions are what I call false starts. It fills its pool, starts to shoot water out, then just stops, the pool empties and you start the approximately hour wait all over. Then when you get an actual eruption, its total duration is probably less than 5 minutes and from what I could find out, Super Eruptions no longer happen.
3. Castle Geyser in the Upper Geyser Basin. This is a cone geyser. Normally predictable eruptions occur 3 or 4 times a day and the predictability is around Plus or Minus half a hour. This geyser shoots water from its cone up to 120 feet in the air. It does this for 15 to 30 minutes and then when it runs out of water, it continues to put out large amounts of steam for sometime afterwards.
2. Riverside Geyser in the Upper Geyser Basin. The is a pool geyser located on the bank of the Firehole River and when it erupts, the eruption goes out across the River. The observation area is on the opposite side of the River from the Geyser and there are some benches provided. This geyser is predictable with a Plus or Minus an hour predictability but where it is located at the bottom of the Upper Geyser Basin it is close to restrooms and is worth the wait.
1. Great Fountain Geyser on Firehole Lake Drive. As its name implies, the area around the geyser pool itself resembles a fountain base area. This Geyser is a pool geyser which means it erups through a pool of water and can reach heights of 200 Feet. It is a beautiful sight to behold but it only erupts a couple of times a day normally, and while predictable to a degree, the predicted eruption time is normally given with a range of Plus or Minus 2 hours so you need to be prepared to take some time to see it and be prepared to wait up to 4 hours to see it. Personally, I think it is well worth the wait.
After reading this list, I hope you begin to understand my overall journal title of "Spend Some Time". When we go to Yellowstone, we always try to stay at least 2 weeks and although we have been several times and have seen all these geysers plus many more erupt many times, it continues to be exciting and highly enjoyable to see them all over again.