The Golden Circle is a very popular route that loops from Reykjavík into the southern uplands of Iceland and back. It is the area that contains most travel-related activities in Iceland. And Kerbyggð is on it!

The three primary stops on the route are the Þingvellir National Park, the Gullfoss waterfall, and the geothermal area in Haukadalur, which contains the geysers Geysir and Strokkur. Other stops include Kerið volcanic crater, the town of Hveragerði, Skálholt cathedral, and the Nesjavellir geothermal power plant. Close to Nesjavellir there is a beautiful hiking area with marked paths.

Þingvellir National Park is one of the most popular tourist destinations in Iceland. It is a site of historical, cultural, and geological significance. The park lies in a rift valley that marks the crest of the Mid-Atlantic Ridge and the boundary between the North American and Eurasian tectonic plates. South of it lies Þingvallavatn, the largest natural lake in Iceland. The park was designated as a World Heritage Site in 2004.
Þingvellir is associated with the Althing, the national parliament of Iceland, which was established at the site in 930 AD. Sessions were held at the location until 1798.

Gullfoss waterfall (Golden Waterfall) is an iconic waterfall located in the canyon of Hvítá river (White River) which is fed by Iceland’s second biggest glacier, the Langjökull. The water plummets down 32 meters in two stages into a rugged canyon which walls reach up to 70 meters in height. On a sunny day shimmering rainbow can be seen over the falls.

Geysir. The English word geyser derives from Geysir. It was the first geyser described in a printed source and the first known to modern Europeans. Geysir has been mostly dormant for many years but Strokkur continues to erupt every 5–10 minutes up to 50 metres (160 ft) in the air.

Only a few minutes away from Kerbyggð is Kerið, a picturesque volcanic crater lake which Kerbyggð is named after. Kerið is 55 meters (180 ft.) deep including the still water on the bottom. There is a path lining the rim for visitors to walk around. There you can view the red and black slopes contrasting with the striking aquamarine water contributing to the otherworldly landscape.

Here is info about the Golden circle:
https://guidetoiceland.is/you-guide/how-to-drive-the-golden-circle