WASHINGTON — New Orleans, in danger seven years ago of being reduced to a ‘‘Sliver by the River,’’ grew faster than any other major US city in the 15 months after the 2010 decennial headcount, the US Census Bureau announced Thursday.

Ravaged in 2005 by hurricanes Katrina and Rita, the city grew 4.9 percent from April 2010 to July 2011, increasing its population to 360,740. In the year after the hurricanes, the population fell to 223,388 from its pre-storm tally of 452,170, the Census Bureau estimated.

The magnitude of population loss after Katrina overwhelmed New Orleans’ protective levees means the city has needed to add relatively few people to rank among the fastest-growing places in the nation since 2007. It also has been aided by US reconstruction dollars and a healthy tourism industry.

‘‘You’re getting a lot of people coming home,’’ said Douglas Brinkley, a Rice University historian and the author of ‘‘The Great Deluge,’’ on the disaster.

New Orleans’ growth rate outpaced six Texas locations among the fastest-rising major US cities: Round Rock, Austin, Plano, McKinney, Frisco, and Denton. Cary and Raleigh, N.C., and Denver rounded out the top 10. New York added the most people, growing by 69,777 for a total estimated population of 8,244,910.

New Orleans has had its problems in the past year. The highest-in-the-nation murder rate spurred Mayor Mitch Landrieu to ask the US government for more help to fight crime.