The Sister Churches () consist of two 12th-century churches that were built right next to each other in Gran Municipality in Innlandet county, Norway. They are part of the Church of Norway and are located in the village of Granavollen. They are part of the Gran/Tingelstad parish which is part of the Hadeland og Land prosti (deanery) in the Diocese of Hamar. The two churches are both gray stone buildings that were both built in a long church design during late-12th century. The church that sits to the north is called St. Nicholas' Church () and the church that sits to the south is called St. Mary's Church (). According to local folklore, the churches were commissioned by two sisters who had fallen out and therefore would not be seen in the same church. It is, however, not uncommon for medieval churches with different functions to be built close to one another. It is more likely that the smaller Mariakirken was a church for a monastery while the Nikolaikirken was a regular parish church. Nikolaikirken The larger of the churches is called Nikolaikirken (St. Nicholas Church). This church probably acted as a church for Hadeland rural parish and can seat around 250 people. Because of later rebuilding it is difficult to establish an exact date of construction, but it is likely that this church is newer than the Mariakirken. Based on stylistic evidence, however, it is thought that the church was built sometime between 1150 and 1200. The church is built as a basilica church with solid Roman columns and plastered walls. The shape and design of the choir was changed during the 13th century and this is also when the large tower was constructed. Much of the original interior has been lost in fires and in subsequent rebuilding over the years. Originally, the tower had a high spire, but it disappeared by a fire in 1799. More of the medieval pieces disappeared from the church during a renovation and modernization during the 1860s. During that construction project, the church was closed and the Mariakirken was used instead. In 1814, this church served as an election church (). Together with more than 300 other parish churches across Norway, it was a polling station for elections to the 1814 Norwegian Constituent Assembly which wrote the Constitution of Norway. This was Norway's first national elections. Each church parish was a constituency that