Steinvikholmen is a fortress located on a small island in the municipality of Stjørdal in Trøndelag county, Norway. It’s a significant historical site, dating back to the Middle Ages. Steinvikholmen Castle, as it is also known, was built in the 16th century by Archbishop Olav Engelbrektsson as a defensive structure and a residence. The fortress played a pivotal role during the tumultuous times of the Reformation in Norway, serving as a stronghold for the last Catholic Archbishop of Nidaros (now Trondheim).

After the Reformation, the fortress lost its original function and gradually fell into disrepair. Today, Steinvikholmen is a popular destination for visitors interested in Norwegian history and medieval architecture. It is accessible to the public during the summer months, offering guided tours that delve into its rich past and significance. The island and the ruins provide a picturesque setting, making it a favorite spot for both educational and recreational visits.