WASHINGTON — The Smithsonian’s National Museum of American History is delaying its reopening from this summer to the fall.

Museum Director Brent Glass said the museum has received inquiries from visitors making travel plans, and wanted to provide them with a more realistic time frame for the reopening. An exact date has not been set.

The museum closed in the fall of 2006 for a $85 million renovation. Some of its most popular artifacts, such as Dorothy’s ruby slippers from “The Wizard of Oz,” are on display at the nearby National Air and Space Museum during construction.

The renovation follows a 2002 blue-ribbon commission report that sharply criticized the museum for its confusing layout and its less-than-inclusive presentation of history.