California cities most densely populated in U.S. U.S. CENSUS

Homes in San Francisco sit close together on Monday, March 26, 2012 in San Francisco, Calif. Homes in San Francisco sit close together on Monday, March 26, 2012 in San Francisco, Calif. Photo: Lea Suzuki, The Chronicle Photo: Lea Suzuki, The Chronicle Image 1 of / 5 Caption Close California cities most densely populated in U.S. 1 / 5 Back to Gallery

California is home to the rugged Sierra Nevada, bucolic vineyards, wave-stroked beaches - and the most densely urbanized areas in the nation.

That's the finding of the U.S. Census Bureau, which on Monday reaffirmed a counterintuitive truth: The cities of the West, barely considered cities at all by many East Coast pundits, often are more densely populated than such skyscraping metropolises as New York and Chicago.

Los Angeles is the nation's most densely urbanized area, with a population of nearly 7,000 people per square mile. The 3.28 million people living in and around San Francisco and Oakland are runners-up, with a density of 6,266 people per square mile.

San Jose places third, with a density of 5,820 people per square mile and a population within its urbanized area of 1.66 million.

These numbers are shaped by commute patterns and geographic features rather than municipal boundaries. But they make sense to people who see in them an affirmation of how the West Coast has evolved since the 1800s.

"It's a legacy of how in our minds' eye we have always separated California into 'urban' land and 'productive' land and then wilderness, the cathedrals of nature," said Jon Christensen, executive director of the Bill Lane Center for the American West at Stanford University.

Not like New York

That's different than such regions as greater New York, which has 18.35 million people in its urbanized area. The 3,450- square-mile area is centered on the vertical island of Manhattan - but it also takes in much of Long Island and forested swaths of Connecticut, areas that feel remote but in fact are tied directly to the core.

"What defines 'urban areas' is not density per se, or residential units, but an integrated job market," said Gregory Ingram, president of the Lincoln Institute of Land Policy in Cambridge, Mass. "Think about the spectrum of (types of) places. ... We have clear ideas of what's at either end, but the suburbs kind of muddy things up."

California, by contrast, has much more rigid lines of separation.

Villages didn't slowly take on a suburban identity, as is often the case in older parts of the country; here, tracts were unrolled across farmland after World War II. Sprawl in turn was hemmed in by state and regional parks or land so steep that development is prohibitively expensive.

The east sides of Marin and San Mateo counties are part of San Francisco's urbanized area, for example, but not the protected western areas of each county.

"In the Bay Area, we have these things together cheek by jowl," Christensen said. "You have a lot of cities packed up against each other, and then the other types of land are very close by."

History also shapes the urbanized areas. Because the area lines were mapped in large part decades ago, San Francisco-Oakland includes portions of southern San Mateo and Alameda counties that now are part of Silicon Valley. But their numbers are credited to the traditional urban hubs to the north, rather than neighboring San Jose.

"The question of where an urban area ends is imprecise," Ingram said. "You sit around a conference table and decide, and then that's what gets replicated over time."

Of the 486 "urbanized areas," only three of the 10 most densely populated are not in California: New York-Newark comes in fifth, "Urban Honolulu" eighth and Las Vegas-Henderson, Nev., 10th.

Small, but dense

According to demographers at the Census Bureau, an urbanized area consists of any concentration of 50,000 or more people. That's how Delano, surrounded by farmland in the Central Valley 30 miles north of Bakersfield with a population of 54,372, is ranked as the nation's fourth most dense urbanized area, ahead of New York-Newark.

The most intriguing nugget found in the density measurements might be the hints that the American norm of growth - ever outward, with densities in a constant decline - might be coming to a halt in certain desirable locales.

That's the case in the San Francisco-Oakland urbanized area, which on the eastern side of the bay stretches from Hercules to Fremont: The population increased 1.6 percent between 2000 and 2010 even as the geographic boundaries shrank slightly.

New York-Newark also grew slightly more dense: Its population is up 3.10 percent, its land area just 2.9 percent.

Similar bumps were recorded in the urbanized areas of Miami, Houston, Washington, D.C., Seattle and San Diego. In the latter - where new condo towers and townhouses fill the once-forlorn downtown - the population went from 2.67 million in 2000 to 2.95 million in 2010. The square miles included in the area, by contrast, dropped from 782 to 732.