Even those that are holding up under the strain are in many cases leaving filers on the line for hours, or kissing them off with an "all circuits are busy" message. Agencies have been scrambling to hire hundreds more workers to handle the calls.
Systems in New York, North Carolina and Ohio were shut down completely by technical glitches and heavy volume, and labor officials in several other states are reporting higher-than-normal use.
"Regardless of when you call, be prepared to wait and just hang on. Try not to get frustrated," said Howard Cosgrove, a spokesman for the Wisconsin Department of Workforce Development, which boosted its staff of telephone operators by 25 percent last month to cope with a phone system that has been overloaded for weeks. "We sympathize, we're on their side, we're doing our best to help them out."
The nation's unemployment rate in November zoomed to 6.7 percent, a 15-year high. Economists predict it will rise to 7 percent in December, with another 500,000 jobs probably cut last month. The government releases its monthly employment report on Friday.
Some states attribute the increase in call volume in part to an extension of federal emergency unemployment compensation from 13 weeks to 20 weeks in late November. More than 54,000 Pennsylvanians had exhausted their federal benefits after 13 weeks by the time that occurred, said David Smith, a spokesman for the Pennsylvania Department of Labor and Industry.
"It really was a perfect storm," he said.
New York's phone and Internet claims system started to buckle on Monday afternoon and was out of service completely for the first half of Tuesday while as many as 10,000 people per hour tried to get in, said Leo Rosales, a state Labor Department spokesman.
Although that was an unusually high number of calls, Rosales said it was a software glitch in an authentication system used to verify filers' identities that caused the system to crash "It's designed to handle this volume of calls, but the authentication process didn't work as it should have," he said.
Rosales said the glitch that caused the shutdown has been fixed, and the agency doesn't expect any more problems.
About 256,000 people are collecting unemployment in New York, up from about 184,000 at this time last year.
North Carolina's Web site crashed twice this week under a rush of claims as that state set one-day records for both the amount of benefits paid and the number of transactions.
On Sunday and Monday, the number of North Carolinians trying to sign up online for new or continuing benefits was about triple what it was before the economic slowdown started, according to the state Employment Security Commission. That volume, together with a phone line problem, overwhelmed the agency's computers and prevented some people from filing claims.
The system was working again by Monday afternoon after the agency added another server and demand decreased, officials said.
"Right now, everything is back to normal," agency spokesman Larry Parker said.
Thousands were unable to get through to Ohio's unemployment hot line beginning Monday because of a crush of callers and technical problems, said Dennis Evans, spokesman for the state Department of Job and Family Services. He said the phone system was running normally again Tuesday afternoon, but the section of the state's Web site that enables people to make claims online remained down.
California has seen a record number of calls to an 800 number over the last few weeks.
"During this holiday period we've been averaging a record of more than 2 million call attempts a day, and it took more than 20 times before people could get through to our UI call centers," said Employment Development Department spokeswoman Patti Roberts.
That's about twice the one-day record of call attempts set in 2004 during an earlier recession, she said.
Callers to Michigan's main phone line handling applications for jobless benefits got an "all circuits are busy now" message Tuesday afternoon. Officials in Michigan, which had the nation's highest jobless rate at 9.6 percent in November, recently began urging applicants to seek benefits through a state Internet site instead. Michigan counted about 473,000 people as unemployed in November, up from about 370,000 a year ago.
Unemployment agencies from Kentucky to Alaska also are reporting long hold times for callers and slowdowns for those filing online because of higher volume.
Several states have added staff to their call centers to handle the surge, including Ohio, Oklahoma and Washington.
Pennsylvania has hired temporary workers and expanded the hours of its unemployment benefits hot line to accommodate a surge in the number of calls, going from 600 employees to more than 800. Officials hope to eventually have 1,100 workers answering calls.
New Mexico has extended call-center hours, upgraded the phone system and added 15 workers. Even so, "We still are receiving reports of people's inability to get through," said Carrie Moritomo, a spokeswoman for the state Department of Workforce Solutions.
Massachusetts officials say they have avoided any technical glitches - but they're straining their system. Right now there are about 200,000 people collecting checks from week to week, up from 107,000 during the same period last year.
"We have reached capacity in our system but we have not crashed," said Michael Taylor, director of workforce development.
In Kentucky, where claims rose to 40,400 in November from 23,400 a year earlier, a flood of new filers overwhelmed the state's unemployment Web site and phone lines on Monday, when more than 8,000 people filed initial claims, said Kim Brannock, a spokeswoman for the Kentucky Education Cabinet, which oversees the state unemployment office.
Kentucky's unemployment systems weren't designed to handle that kind of volume. Technicians worked through the night to add capacity to the Web site and are still trying to increase its phone capacity beyond the current 400 lines, Brannock said.
"People seem to feel like they have to file first thing Monday morning," she said. "They don't have to, but they feel that way. It's just overwhelming to the system."