The amount was confirmed to The Associated Press by two campaign officials speaking on condition of anonymity because the numbers haven't been made public.
The McCain campaign is on track to meet its internal budget goal of about $57 million through the start of the Republican convention and an additional $20 million for a legal compliance fund, reports CBS News chief political consultant Marc Ambinder.
One official said McCain intends to accept public financing in the general election - a sum of about $84 million. McCain donors are now being asked to supplement that public financing with donations to the Republican National Committee, with a goal of raising $120 million through a joint Victory Committee.
The March fundraising and the decision to seek public financing in the fall are two separate tracks that highlight the superior fundraising by the Democratic candidates.
Obama raised $40 million in March, bringing his total so far in the campaign to about $234 million. Clinton raised $20 million for a total of more than $175 million during the entirety of the contest. McCain has raised about $75 million since he began running last year.
Clinton has raised at least $22 million for the general election and is expected to raise her own money if she is the Democratic nominee. Obama, who once said he would take public money if his Republican rival did as well, has made no commitment and is under pressure to use his formidable fundraising in the general election as well.
No presidential candidate has rejected public financing in the general election since the post-Watergate campaign finance reforms of the 1970s. The money is financed by taxpayers who check off a $3 dollar allocation to the presidential fund in their tax returns.
By setting up a joint fundraising committee with the national Republican Party, McCain can maximize the donor power of his contributors. Donors who contribute to the Victory Committee could give up to $30,800. Of that, $28,500 could go to the party and $2,300 to McCain, provided they had not donated to McCain before. Previous McCain donors could still contribute the maximum $28,500 to the party.
Details of the candidates March fundraising won't be known until they file their reports with the Federal Election Commission April 20.