Lachlan, born about 1820, was the eldest child of Archie Munro and Mary MacLeod of old Ruisgarry. In 1850 he moved with his widowed mother to croft 20 Ruisgarry (Brusda) which was later passed to him. Lachlan became a farmer/crofter, and was passed 20 Ruisgarry following his mother's death in 1864. He was a Free Church missionary, at one time in the Borves, Harris. He was one of two men from Berneray who gave evidence at the Napier Commission at Obbe in 1883.

Lachlan married Margaret MacLeod, from 304 Kilpheder though born on Berneray. They had no children. Following Lachlan's death the croft was passed to nephew John Munro.