Loingsech mac Colmáin (died 655)[1] (or Laidgnén) was a king of Connacht from the Ui Fiachrach branch of the Connachta.
He was of the Ui Fiachrach Aidhne sept this branch and was the son of Colmán mac Cobthaig.
[3] Loingsech succeeded Rogallach mac Uatach (died 649) of the rival Uí Briúin branch as king of Connacht in 649.
Rivalry between the Ui Fiachrach Aidhne and Uí Briúin is attested by two events that occurred in his reign.
Lairgen's supposed marriage to Deoch, daughter of Finghin, is said to have been the "coming together of the Man from the North and the Woman from the South," which broke the 900-year curse upon the children and returned them to human form.