Minneapolis' population has surpassed 400,000 for the first time since the mid-1970s, a striking reversal from decades of population decline and stagnation.

Preliminary estimates also show St. Paul edged past 296,000 in 2013 after what was, for both cities, the largest annual population increase since at least 2000, according to Metropolitan Council data. Those figures, based largely on housing trends, could change before they are certified in July.

The core cities' growth comes as cities nationwide are reclaiming populations lost to the suburbs in the latter half of the 20th century. Demographers find that young people are increasingly choosing to live in urbanized areas rich in amenities, diversity and transportation options. Also, more elderly people want to stay in the city.

Minneapolis's population fell steadily from its peak of about 521,000 in 1950 and, despite some 1990s growth, remained virtually unchanged between 2000 and 2010. But growth since 2010 now appears to gaining momentum as new apartment and condo buildings rise in downtown and the North Loop, Uptown and University of Minnesota neighborhoods.

The boom is embodied by people like Dave Michela and his partner, who lived in Twin Cities suburbs for more than a decade. They will move from Golden Valley into a new condo in the Mill District this July.

"Our lives really revolve around downtown," said Michela, a vice president for a Minnetonka tech company. "We'd leave our work in the suburbs, go home to change and go downtown. It just made perfect sense that we would try to relocate."

Michela said that their attraction to urban living has grown in lockstep with a growing list of downtown amenities, including new grocery stores and parks. The development of Downtown East has only made it more attractive.

"Downtown is a now a viable residential community that is not going to ebb and flow with the whims of the market," he said. "It's an established place where people want to be."

Based on the new figures, Minneapolis added 8,930 residents between 2012 and 2013, up from 5,295 the year before, bringing the city's 2013 population to 400,938. The city issued permits to build 3,552 new units in 2013, valued at $1.2 billion altogether.

"The big takeaway here is that the pace of our growth is accelerating," said Minneapolis Mayor Betsy Hodges. "And that's exactly what I want to see."

Hodges has set a goal of eventually surpassing 500,000 residents, which she said will require adding dense housing along transit routes. She is hesitant to give an exact date for that goal, but said Wednesday she would like to reach it "in the next couple decades."

Some are skeptical whether reaching 500,000 residents is possible in the near future. The average household size in Minneapolis is now 2.24, down from 3.08 in 1950. Minneapolis already has more households than it did in 1970, for example, despite having about 30,000 fewer people.

Ed Goetz, director of the Center for Urban and Regional Affairs at the University of Minnesota, said that because of these trends, hitting the half-million mark would require a "much more significant sort of adjustment to the infrastructure and to settlement patterns."

Hodges' response: "Communities that are growing well across the country are facing the same issue we are and they are still successfully growing."

In fact, Minneapolis grew more slowly between 2010 and 2012 than some of its peer cities, such as Denver, Portland and Seattle. Hodges said she would like the pace to accelerate, though she added that the city has learned to better manage growth during the ramp-up.

The Metropolitan Council is in the process of completing its "Thrive MSP 2040" 30-year planning document, which projects that Minneapolis will reach a population of just under 465,000 by 2040, while St. Paul will hit 334,000.

Minneapolis leaders have criticized those forecasts, which altogether project that Minneapolis and St. Paul will account for a smaller share of the metro-area population in 2040. Council President Barb Johnson is doubtful the city can reach 500,000, but believes there is plenty of room to grow in places like north Minneapolis.

"In this fully developed city, we have neighborhoods which have huge volumes of available lots, because of foreclosures and tornadoes and all the other things that have happened in north Minneapolis," Johnson said during a recent hearing on the Thrive plan.

North Minneapolis was a major reason why the city's population remained largely flat between 2000 and 2010. Census data compiled by the city show that distressed North Side neighborhoods like Jordan and Hawthorne hemorrhaged residents during the decade, while downtown, the North Loop and university areas boomed.

So who accounts for the population increase? A report presented to city leaders by the Urban Land Institute recently shows that households headed by 55- to 74-year-olds increased by 35 percent between 2004 and 2011, while households of 24- to 35-year-olds rose by 6.6 percent. Households headed by those ages 35 to 54 fell by 6.7 percent, however, something that has caught the attention of the city's long-range planner, Kjersti Monson.

Monson expects many of those families are having second children and growing out of their homes. "I would attribute that to, in part, our housing stock," Monson said, adding that the city needs to understand more about what's available to those families.

Staff writer Jim Buchta contributed to this report.

Eric Roper • 612-673-1732

Twitter: @StribRoper