The move is expected to breathe new life into the estate on the Isle of Harris.
Roseanna Cunningham, the environment minister, made the formal handover of the 16,247-acre Borve, Luskentyre and Scarisatavore estates to the West Harris Trust.
The trust is the first community body to take advantage of the Transfer of Crofting Estates (Scotland) Act, introduced in 1997 by the then Scottish secretary Michael Forsyth.
It plans to build new affordable housing, create jobs and develop renewables and tourism to help reverse chronic depopulation.
The trust says two young women have already indicted they wish to return to settle in the area with their partners.
Ms Cunningham, who signed the historic handover in the tiny village school at Seilebost, said: "This land transfer is the culmination of a great deal of hard work, determination and commitment on the part of the West Harris Trust.
"Community ownership plays a very important role in the empowerment of communities: it improves self-reliance and offers opportunities for employment, skill development and economic success."
The three estates, which have a total of 52 crofts, were sold for 59,000, a price determined by the Valuation Office Agency. The trust received 23,600 from Highlands and Islands Enterprise Community Land Unit, 15,000 from Comhairle nan Eilean Siar (Western Isles Council) and 10,000 from the Big Lottery Fund.
In addition housing agency Tighean Innse Gall has provided 20,000 and the Scottish Government covered the legal costs of the transfer.
Murdo Mackay, a crofter and chairman of the West Harris Trust, said: "We want to promote Harris as a great place to live and work and we hope to get more families into the area and create new crofts and bring currently under-used land into production.
"We are very excited about the fact that control of our own land will breathe new life into the community and encourage people to set up homes and raise families."
Council convener Alex MacDonald said the move is another historic milestone for the Western Isles: "After three years of efforts, the buyout will hopefully secure the future of the area and reverse the decline in population as well as improving economic activity."
Between 1951 and 2001 the population of Harris fell by over half from 3,991 to 1,984. At present around 37 per cent of residents are over 65.
At the same time school rolls are falling. Numbers at Seilebost primary in West Harris have dropped from 21 in 1971 to 11 this year and there is only one pre-school child in the area.
Another community-run trust owns the 55,000-acre North Harris Estate, bought in 2003, and the neighbouring 7,472-acre Loch Seaforth Estate meaning more than 60 per cent of Harris is already in local hands.