BOSTON (Reuters) - Democrat Elizabeth Warren raised $3.15 million in the first stage of her bid for the Senate from Massachusetts, the former Obama administration official's campaign said on Monday.

More than 11,000 individuals in Massachusetts alone gave to Warren's campaign, and the vast majority of the contributions were $100 or less.

The fundraising haul, which only covers a portion of the third quarter, is a strong start for Warren, who would face Republican Scott Brown in November 2012 if she wins the Democratic primary in September.

The only other Democratic candidate in the primary to announce fundraising totals so far, community organizer Alan Khazei, said on Friday he raised $365,000 in the third quarter and had $750,000 available.

Brown's campaign has raised at least $3.7 million so far this year and has $9.6 million on hand. He has not released third-quarter figures.

The moderate Republican won a special election in January 2010 to fill the remainder of the late Senator Edward Kennedy's term. Kennedy died of a brain tumor in August 2009.

Republicans are eager to hold Brown's seat, and Democrats see it as perhaps their best chance to pick up a seat in 2012.

Warren, a Harvard University law professor, announced her Senate run on September 14, but started raising money in August, when she formed an exploratory committee.

Progressive groups, including MoveOn.org, have thrown fund-raising muscle behind Warren, a consumer advocate and Wall Street critic.

Warren created the Obama administration's Consumer Financial Protection Bureau and led a panel created by Congress to examine how bank bailout money was being spent.

(Reporting by Ros Krasny; Editing by Doina Chiacu)