As a symbolic gesture, the bill also gifts four islands to the collective, which will then give them back to the Crown, except for the summit of Rangitoto and two small sites where historical waka were moored.
The sites will be governed by a new body - the Maunga Authority - made up of representatives from the collective and the Auckland Council.
Mayor Brown called the bill "one of the most historic pieces of legislation for Auckland".
"It's a time of real change, a shift from iwi looking backwards and having to deal with things that were wrong in the past, to shared governance of the cones.
"Sometimes we didn't do a very good job [looking after the sites] in the past under old councils, but under joint governorship, my hope is that we'll do a better job, and they'll be treated as key parts of our natural landscape."
Treaty of Waitangi Negotiations Minister Chris Finlayson hoped the authority would continue to push for Unesco World Heritage status for the volcanoes, in collaboration with the Ministry of Culture and Heritage.
"If someone wants to go for a walk up Mt Eden, are they going to notice any dramatic change? No.
"But over time, I think they'll see remediation of some of the maunga, and then they'll see, especially if the World Heritage thing goes through, a very significant change."
Mr Brown was confident the council would find the funds to properly manage the sites. The council is under huge financial pressure and has to find $2.8 billion over the next 10 years to keep rates at 2.5 per cent, in order to maintain its existing budget.
The chief Crown negotiator for Tamaki Makaurau, Michael Dreaver, described the land transfer as a "downpayment" that preceded Treaty claims from individual iwi and hapu, which were still in progress.
He said many of the historic land purchases that included the volcanoes were for too much land, for too low a price, and not always bought from the right tribes.
Like many Treaty settlements, the bill includes a right of first refusal for 172 years over surplus Crown-owned lands in the region - including property owned by Auckland University and Unitec Institute of Technology.
The land must firstly be offered to the collective on the same or better terms - except for special cases, such as for charitable, state housing, or conservation purposes.
"Over the years, one came imagine that's going to turn up some very interesting opportunities for the iwi," Mr Finlayson said.
The Maunga Authority will look after 12 of the 14 sites, and Crown-owned Mangere Mountain. Regional Facilities Auckland will look after Rarotonga/Mt Smart, and the Department of Conservation will look after Maungauika/North Head.
The bill does not settle any historical claims, but was thought to be the best way to address the overlapping interests of several iwi in the volcanoes.
- additional reporting: James Ihaka
