Vikna is a large island archipelago and a former municipality in Trøndelag county, Norway. The municipality existed from 1869 until its dissolution in 2020 when it joined Nærøysund Municipality. It was part of the Namdalen region. The administrative centre of the municipality was the town of Rørvik. Other villages in Vikna included Austafjord, Garstad, and Valøya. At the time of its dissolution in 2020, the municipality was the 269th largest by area out of the 422 municipalities in Norway. Vikna was the 221st most populous municipality in Norway with a population of 4,492. The municipality's population density was and its population had increased by 11.4% over the last decade. The municipality of Vikten was established on 1 July 1869 when it was separated from the large municipality of Nærøy. Initially, the population of Vikten was 1,749. On 1 January 1881, a small area of Fosnes (population: 61) was transferred to Vikten. The name of the municipality was later changed to Vikna. On 1 January 2018, the municipality switched from the old Nord-Trøndelag county to the new Trøndelag county. On 1 January 2020, the municipality of Vikna was merged with most of the neighboring municipality of Nærøy to form the new Nærøysund Municipality. The Lund area in Nærøy was not part of the merger. It became part of the newly enlarged Namsos Municipality on the same date. The municipality (originally the parish) is named "Vikna" or historically Vikten. It was named after the three large islands which made up the municipality: Inner-Vikna, Mellom-Vikna, and Ytter-Vikna (Víkn). The name is derived from the word vík which means "cove" or "wick" (likely since the islands have numerous coves and inlets. The coat of arms was granted on 13 May 1988 and it was in use until 1 January 2020 when the municipality was dissolved. The official blazon is "Azure, three salmon argent in annulo" (I blått tre sølv lakser som danner en sirkel). This means the arms have a blue field (background) and the charge is three salmon forming a circle.