Thrihnukagigur volcano is ideally located, midway between Reykjavik and the Golden Circle area. It takes around 30 minutes to drive from the city to the parking lot outside Blue Mountain cabin (meeting point), from where the hike needed to reach the crater starts.
As the below map shows, the volcano is not far from some of the most popular tourist attractions in Iceland, such as the Blue lagoon, Gullfoss waterfall, the Geysir hot spring area and Thingvellir National Park. Hence, a trip to the Thrihnukagigur volcano can easily fit into a route that includes those attractions.
Click here for detailed instructions on how to get there.