Namdalseid is a former municipality in Trøndelag county, Norway. The municipality existed from 1838 until its dissolution in 2020 when it joined Namsos Municipality. It was part of the Namdalen region. The administrative centre of the municipality was the village of Namdalseid. Other villages and farm areas in the municipality included Sjøåsen, Statland, Tøttdalen, and Sverkmoen.

Trøndelag (Urban East Norwegian: [ˈtrœ̂ndəˌlɑːɡ]; or Trööndelage  is a county and coextensive with the Trøndelag region in the central part of Norway. It was created in 1687, then named Trondhjem County ; in 1804 the county was split into Nord-Trøndelag and Sør-Trøndelag by the King of Denmark-Norway, and the counties were reunited in 2018 after a vote of the two counties in 2016.