WASHINGTON—U.S. mortgage debt reached a record in the second quarter, exceeding its 2008 peak as the financial crisis unfolded.

Mortgage balances rose by $162 billion in the second quarter to $9.406 trillion, surpassing the high of $9.294 trillion in the third quarter of 2008, the Federal Reserve Bank of New York said Tuesday.

Mortgages are the largest component of household debt. Mortgage originations, which include refinancings, increased by $130 billion to $474 billion in the second quarter. The figures are nominal, meaning they aren’t adjusted for inflation.

“The big picture is that when you look at mortgages, which is the biggest piece of [household debt], it still looks pretty healthy,” said Michael Feroli, chief U.S. economist at JPMorgan Chase, noting that while household debt has grown, so have incomes.

The milestone for mortgage debt has been long in the making. Americans’ mortgage debt dropped by about 15% from the 2008 peak to the trough in the second quarter of 2013 and has climbed slowly since then.