When I first started researching for Iceland I kept getting confused about what "Golden Circle" was, and confused it with the ring road. So here is an overview for your benefit:
- The Golden Circle is a short, ~180mile (~300km) loop of highway just to the east of Reykjavik
- It's famous because it's easily accessible from Reykjavik, and can be toured in 1-2 days, so it's extremely popular with tourists and short layover visitors
- Personally, I think the Golden Circle showcases only one facet of Iceland. It's extremely well developed for tourism and not too far from the built-up areas that you will not experience a sense of wilderness here (you'll mainly see farms on both sides of the roads), and it doesn't have the interesting geological features you see in the western, southeastern, and northern part of the country that make Iceland so wonderful
- You can either drive it yourself or join one of the many organized tours from Reykjavik. Again, this area is so well developed for tourism that it's very easy to see it and get around
Here's a map of the golden circle and the main things to do (click on the markers for more info):
The main things to see in the Golden Circle are:
- Þingvellir National Park (pronounced like "thing-vel-leer"): it's a famous park for both natural and cultural heritage. Iceland's first parliament was held on a rock here. Most people come here for day hike, and to dive at Silfra, which is a crack between the North American and European plates. It's the only place in the world where you can swim/dive between two continents
- Blue Lagoon: technically outside the Golden Circle, but it's close enough to it that I consider it part of the Golden Circle. It's a very popular and famous hot spring, whose water is known to have health properties. You need to book it 4-6 days ahead of time online, and it's not cheap. Blue Lagoon is NOT natural, it's completely man made. The water comes from the nearby geothermal power plant that extracts very hot water underground to produce electricity, after which the water is discharged to the Blue Lagoon for bathing
- Geysir: the English word "Geyser" originated from this. It's literally a giant geyser that erupts every 5-10 minutes. It's extremely popular and the area around it is built up with a giant shop and a hotel
- Gullfoss: one of the larger waterfalls in Iceland
- Secret Lagoon: a competitor to Blue Lagoon. It's another private hot spring you can bath in. It's much less crowded and cheaper than BL. It's nowhere near as fancy though. I read one reviewer characterized has "quaint"
- Reykjadalur Hot River: a completely natural river 60-min hike up in the mountains whose water is just hot enough to bath in comfortably. I went first thing in the morning before it got crowded and it was fantastic. The water isn't very deep and is very calm. Perfect place to chill after an intense uphill hike
- Kleifarvatn: a remote and nice lake. Technically not on the golden circle but close enough. When the weather is nice it's a great place for a hike. If you like Black Mirror, the opening scene of Crocodile episode in season 4 was filmed here
- Krýsuvík Geothermal Area: it's an area with fumaroles (vents that carry volcanic gas to the surface). It's like a smaller and less eventful version of Geysir. Technically not on the golden circle but close enough.