Hosanger is a former municipality in the old Hordaland county, Norway. The municipality existed from 1838 until its dissolution in 1964. The municipality was located in what is now parts of Alver Municipality and Osterøy Municipality in Vestland county. It originally covered all the lands on both sides of the Osterfjorden-Romarheimsfjorden from the Lonevågen fjord all the way east to the county border at the end of the Modalen valley. Hosanger also included an exclave on the Lindås peninsula surrounding the village of Seim at the southern end of the Lurefjorden. Seim was separated from the rest of Hosanger by part of Lindås Municipality. Over time, the areas of Seim and Modalen were split off from Hosanger. The administrative centre of the municipality was the village of Hosanger on the island of Osterøy, where Hosanger Church is located. The parish of Hosanger was established as a municipality on 1 January 1838 (see formannskapsdistrikt law). On 1 January 1885, the exclave of Seim was separated from Hosanger and merged into the new Alversund Municipality. This left Hosanger with 3,387 residents. On 1 January 1867, the Øksendalen farm (population: 28) in the Eksingedalen valley was transferred from Voss Municipality to Hosanger by Royal resolution. On 1 January 1910, the eastern part of Hosanger (population: 821) which included the Modalen and Eksingedalen valleys was separated from Hosanger to form the new Modalen Municipality. The split left Hosanger with 2,524 inhabitants. During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. On 1 January 1964, the municipality of Hosanger was dissolved and its lands were divided as follows amongst its neighbors: All of Hosanger located north of the Osterfjorden (population: 791) became a part of the enlarged Lindås Municipality. All of Hosanger located on the island of Osterøy (population: 1,616) became a part of the new Osterøy Municipality. The municipality (originally the parish) is named Hosanger (Hosangr) which was the old name of the local bay, now known as the Mjøsvågen.