The first government shutdown in nearly seven years left federal agencies in flux and many of their employees in a state of confusion on Wednesday, as they received last-minute and conflicting instructions from managers.

Even though the likelihood of a shutdown has been high for months, agencies were late to post their contingency plans compared with previous years, leaving employees and the public in the dark about what to expect. And internal guidance to work forces in some cases was not consistent with the official plans. Some employees who expected to be furloughed learned on Wednesday that they had to report to work.

But despite the uncertainty inside the government, the initial ripple effects across the country were scattered and limited.

There was no major disruption to air travel. The Internal Revenue Service answered calls from taxpayers. And federal agents arrested immigrants who showed up for routine court appearances in Lower Manhattan.

But the impact was felt elsewhere. The Jimmy Carter Presidential Library in Atlanta was closed, and visitors got a quick civic lesson: Presidential libraries are operated by the federal National Archives and Records Administration, which furloughed more than half of its staff.

“We thought it was privately funded, or we would have come yesterday,” said Cindy Mobley, 64, of Baltimore. Ms. Mobley and her husband were in town visiting their son, a freshman at nearby Emory University.