Gullfoss (translated as "Golden Falls") may be Iceland's most popular waterfall, and we can certainly testify to that statement given how it was always busy during our visits. This was in part because it was one of three major attractions on the Golden Circle Route (or Tour) that included Geysir and Þingvellir as a very doable day trip out of Reykjavík. Nonetheless, the waterfall's popularity was well-deserved because it was one of the more unique ones we've seen. In fact, we thought it was both spectacular and memorable enough to earn a spot on our World's Top 10 Waterfalls List.
What made Gullfoss stand out to us was that it featured two distinct drops in succession at right angles to each other while spanning the entire width of the Hvítá River. Adding to the scenic allure was that the river flowed wildly and freely so it could be experienced in all seasons as each season would yield very different moods and appearances. Our visit happened to be during the Summer so it produced beautiful rainbows in its wafting mist when the afternoon sun came out. The glacial coloring of the river (since its source has glacial origins) also became very apparent when the sun came out as well.
The upper drop was said to have a height of 11m while the lower drop was said to have a drop of 21m for a total cumulative drop of 32m high. However, when the falls was viewed from the main overlooks near the visitor facilities, the lower drop fell into a narrow gorge creating the illusion that the waterfall would plunge into an abyss. That effect made the falls appear higher than its modest height would suggest.
It's hard to believe that this waterfall almost disappeared due to the desire for hydroelectricity by various interests. In some fortuitous bit of misfortune (at least for those with development aspirations) resulting in lack of sufficient funds, attempts to harness the falls had been unsuccessful. Ultimately, the waterfall was sold to the state of Iceland, and despite further interest to utilize the river by the state, it was eventually conserved.
A more romantic saga depicted Sigríður Tómasdottir (the daughter of the landowner who was about to sell his land which included the falls) threatening to throw herself into the falls if the land was sold. As a result, the father pulled out of the deal, the falls was made a reserve, and the rest was history. It's said that this saga isn't true, but nonetheless we saw there was a memorial at the falls commemorating Sigríður Tómasdottir.
In addition to the hordes of tourists who are both self driving and on various tours, we also shared this waterfall with hordes of midges, which seemed to be abundant in the early Summer. We don't know if the midges persist at other times of the year, but they were definitely a nuissance during our visits.
As for experiencing the waterfall, we parked at the car park closest to the visitor facilities (see directions below), then we walked past the facilities onto a boardwalk that took us to an overlook of the falls. This was the view you see at the top of this page.
Then, we followed a trail that descended steps towards the lower car park where there was a trail that led alongside the gorge carved out by the falls as it led to brinks of both the lower and upper tiers of Gullfoss. To our knowledge, there wasn't a way to experience the falls from the other side of the river, but it wasn't necessary in our minds.
In any case, the walking would probably comprise no more than 15 minutes or so total. A few more minutes might be needed to walk all the way to the brink of the falls.
Directions: From Reykjavik, drive about 54km east along the Ring Road to the turnoff with route 35 on the left. Follow route 35 for over another 68km or so to the waterfall, passing by Geysir (another Golden Circle main attraction) along the way.
There are actually two car parks for the falls - a lower one off route 334 and a much larger upper one next to a visitor centre off route 35. The turnoff for route 334 is about 700m before the larger car park off the route 35.
Although it's a little bit of a longer walk from the larger car park to get close to the falls, I personally don't think it matters much where you park unless you're elderly or disabled in which case the lower car park would be the desired option. We noticed that most of the tour buses tended to stop at that car park.