Banks repossessed a record one million US homes in 2010, and could surpass that number this year, figures show.
Foreclosure tracker RealtyTrac said about five million homeowners were at least two months behind on their mortgage payments.
Foreclosures are likely to remain numerous while unemployment remains stubbornly high, the group said.
Among the worst hit states were Nevada, Arizona, Florida and California, once at the heart of the housing boom.
Nevada had the highest foreclosure rate for the fourth year in a row, with one in 11 housing units receiving a foreclosure notice, and RealtyTrac said more than half the nation's foreclosures occurred in Arizona, California, Florida, Illinois and Michigan.
RealtyTrac said 2.9 million US households were subject to a foreclosure filing last year, up 1.67% from 2009.
"2011 is going to be the peak," senior vice-president Rick Sharga told the Associated Press news agency.
Foreclosures slowed toward the end of 2010 amid revelations that banks had based the proceedings on improper documentation, but the pace is likely to rebound in the first quarter of 2011, Mr Sharga said.