The Department of Homeland Security is, by all accounts, not the easiest place to work. The pressure is high, the job is hard and morale in recent years has been about as low as it can get.

But perhaps the most universally frustrating part of working for DHS, according to numerous former and current officials, is the byzantine congressional oversight.

More than 90 committees and subcommittees have some jurisdiction over DHS, nearly three times the number that oversee the Defense Department. And that doesn’t count nearly 30 other congressional bodies such as task forces and commissions.

“It makes no sense at all,” said Rep. Peter King (R-N.Y.), a homeland security committee member, who attributed the structure to a “petty fight for power” between committees reluctant to give up their piece of DHS.

The dispute dates to 2002, when the department was formed by mashing 22 autonomous federal agencies into one. Those agencies had reported to various congressional committees, and those committees have been unwilling to give up their roles overseeing DHS’s components.

“It makes it very difficult for the department,’’ said King, who sees “no movement” in Congress to change the situation. “The amount of time that goes into preparing for a congressional hearing is immense. It’s like this hydra-headed monster they have to deal with.’’

Indeed, some former DHS officials said it often seemed like they had little time to deal with much else.

Between January 2009 and last month, DHS officials testified at nearly 800 congressional hearings and had a total of 10,584 “non-hearing engagements” with Congress, which includes such contacts as meetings and briefings, according to statistics the department provided. Even that number does not include e-mails exchanged between DHS and congressional staff members and DHS reports prepared at Congress’s request.

People familiar with the numbers said they are significantly higher than comparable totals for other large Cabinet agencies such as the Defense and State departments.

And, for anyone who may think the oversight issue is just a Washington turf battle or insider baseball, the 9/11 Commission has an answer: it actually threatens the nation’s security. In a recent follow-up to its earlier report on the Sept. 11, 2001 attacks, the commission blasted Congress for what it called the “unwieldy hodgepodge of committees.’’

“Reporting to this vast array of committees also places an extraordinary administrative burden on DHS, which must prepare reams of written testimony and respond to countless questions for the record,’’ the report said. “This burden distracts from other, higher-priority tasks.’’

The report concluded: “This Balkanized system of oversight detracts from the department’s mission and has made Americans less safe.’’