The deadline to sign up for insurance on the federal government's health care website arrived Tuesday, a day later than expected after the Obama administration granted those waiting until the last minute -- or those tripped up by the site's glitches -- an extra day to enroll.



The one-day grace period for those using the federal exchange was the latest in a series of delays that have marked the rollout of the health care law.



Thirty-six states, including Virginia, rely on the federal website for enrollment. The remaining 14 states, including Maryland, and the District of Columbia have their own exchange websites.

The deadline for D.C. residents has already passed. They had until midnight Monday to sign up. Residents of Maryland have until Friday.



Officials said they decided to extend the federal deadline to Christmas Eve to ensure people in different time zones and those experiencing technical problems that might result from a last-minute rush of applicants can sign up successfully.



Among those not needing the extra day: President Barack Obama. The White House said Monday he had signed up for coverage through the new insurance exchange, even though he won't use it. And Obama aides didn't actually use the healthcare.gov website to sign up their boss, a reminder of just how complex the process can be.



Had Obama tried to log on Monday afternoon, he would have been among the record 850,000 visitors to healthcare.gov, five times the number logged by the same time last Monday.



Julie Bataille, a spokeswoman for the federal agency in charge of the health care overhaul, said the system was handling the volume with error rates of less than 1 in 200 and response times of less than one second.



Still, critics of the law said the grace period is yet more evidence that the website still isn't working and that Obama keeps changing the rules. In Ohio, Lt. Gov. Mary Taylor called the deadline extension "a clear sign Healthcare.gov continues to struggle."



"Consumers are already confused and insurers are overwhelmed with the administration's last-minute changes, yet there seems to be no end in sight," said Taylor, a Republican who heads Ohio's insurance department.



Monday had been the deadline for Americans in the 36 states served by the federal site to sign up if they wanted coverage at the start of the new year. The remaining states operate their own online marketplaces, and some of them have also extended their deadlines.



The federal site had a disastrous, glitch-prone debut in October but has gone through extensive improvements to make it more reliable and increase its capacity. The Obama administration is hoping for a surge of year-end enrollments to show that the technical problems were merely a temporary setback.



That would also go a long way toward easing concerns that insurance companies won't be able to sign up enough young, healthy people to keep prices low for everyone.

The administration was careful not to characterize Tuesday as a new deadline or an extension, likening the move instead to the Election Day practice in which people who are in line when the polls close are still allowed to vote.



As the deadline drew near, more than 1 million people visited the website over the weekend, and a federal call center received more than 200,000 calls.



The government's original deadline already had been pushed back a week because of the website problems. The extra day will add to the already daunting administrative problems that insurance companies face, such as inaccuracies on applications, said industry consultant Robert Laszewski.



"Insurers would like to have two to three weeks to process applications. Now they're going to have a week, less one more day," he said. "When the day is done, it doesn't help."



Obama said Friday that more than 1 million Americans had enrolled for coverage since Oct. 1. The administration's estimates call for 3.3 million to sign up by Dec. 31, and the target is 7 million by the end of March. After that, people who fail to buy coverage can face tax penalties.



Minnesota, one of the states running their own insurance exchanges, extended its Monday deadline to Dec. 31 amid problems with its website and extra-long hold times to reach its help center. Maryland pushed back its cutoff date to Dec. 27. New York extended its deadline to midnight Tuesday.



Nevada stuck to its Monday deadline, and enrollment counselors there reported a surge of interest.



"We have people lined up out our door. We still have walk-ins, people are asking for help. Our phones are ringing nonstop," said Andres Ramirez in Las Vegas.