Bridges wrote Uttermost Part of the Earth (1948) about his family's experiences in Tierra del Fuego, the Yahgan and Selk'nam indigenous peoples, and the effects on them of colonization by Europeans.

Thomas Bridges was an Anglican missionary who ministered to the indigenous Yahgan and Ona peoples, and the first foreigner to establish a permanent outpost in the Usi Yagán, or Yaghan country, in the area currently known as Beagle channel.

[2] He also compiled a vocabulary of the Haush or Manek'enk, a small indigenous tribe who lived to the east of the Selk'nam, at the end of Mitre Peninsula.

[3] In 1886 Thomas Bridges resigned his position as a missionary; Lucas helped his father to create the Estancia Harberton (named after his mother's hometown in England), a sheep farming ranch, in a sheltered bay on the coast of the Beagle Channel.

In 1898 Lucas Bridges opened a trail north from Estancia Harberton to the east end of Lago Fagnano, where the land was better for rearing sheep.

Lucas Bridges became the main informant for almost every traveler, national explorer or international anthropologist in the area, and was quoted in most reports on the indigenous peoples of Tierra del Fuego.