This isn't your grandfather's urbanization: population figures in major U.S. cities, which on the whole are on the uptick after declining in the 1960s, are adding residents not to their already built urban cores but rather in the form greenfield sprawl, which makes use of farmland and lightly developed suburban housing tracts. The big exception? Los Angeles, whose urban core Slate pronounces full. Here's more detail from the piece:

A new and illuminating analysis by Yonah Freemark, a project manager at Chicago’s Metropolitan Planning Council and the author of the Transport Politic blog—well worth reading in full—reveals some important trends in the past half-century of city-building...

 “The average of the 100 largest cities grew by 48 percent overall,” Freemark notes. “Yet the average city also lost 28 percent of its residents within its neighborhoods that were built up in 1960.” That’s not just true in Youngstown and Detroit, post-industrial Rust Belt cities that have struggled with blight. Houston, Dallas, Charlotte, Las Vegas, and Nashville, to name just a few booming cities, have all lost people in built-up, midcentury neighborhoods. In fact, Freemark shows, inner-core residential decline in Southern cities is virtually identical to that in Midwestern cities, despite divergent population trends in the cities at large. Older, denser, inner neighborhoods are, in almost every city, much less populous now than in 1960...

But Los Angeles and Long Beach have together added more than a million people to urban areas since 1960.

The shifting reality of Los Angeles in the news:

• A 'radical alternative': how Reyner Banham changed the perception of Los Angeles
• Is Los Angeles becoming a "real" city?
• Alissa Walker imagines a "utopian" Los Angeles in 2056