They're three of America's best-known college towns.

They're also the three leaders in brainpower among the nation's major cities.

Ann Arbor, Mich.; Cambridge, Mass.; and Berkeley, Calif., hold the top three places in On Numbers' analysis of educational attainment in 269 communities with more than 100,000 residents:

• Seventy-two percent of all adults (25 or older) hold bachelor's degrees in Ann Arbor, the home of the University of Michigan, and 43 percent also have advanced degrees.

Both figures are the best in their respective categories among all major cities.

• Cambridge, the site of Harvard University, is a close second in both categories and consequently is second in the overall rankings.

• The only other big city where more than 36 percent of all adults have advanced degrees is Berkeley, the location of the University of California.

On Numbers devised a five-part formula to rate the brainpower of communities across America, using raw 2009 data from the U.S. Census Bureau's five-year American Community Survey.

Each place's score was based on its percentage of adults at each level of a five-rung educational ladder:

• Dropped out before high school graduation

• Stopped at high school diploma

• Stopped at associate degree or attended college but stopped without any degree

• Stopped at bachelor's degree

• Earned graduate degree and/or professional degree

The point value of a specific rung was determined by the relative earning power of people at that level, based on Census Bureau research.

Ratings for the 14,214 communities in this category and the three classifications below can be found on online databases at http://tinyurl.com/on-numbers.

Eleven California cities rank among the top 50 on the list of major cities, easily the best performance by any state. Arizona and Texas are a distant second with four entries each.

Bethesda, Palo Alto rank 1-2

Bethesda, Md., and Palo Alto, Calif., are the smartest communities with populations between 50,000 and 99,999, according to On Numbers' analysis:

• Bethesda, which ranks No. 1 among 483 cities and towns in the 50,000-to-99,999 group, is an upscale Washington suburb.

• Palo Alto, a close No. 2 in the brainpower rankings, is located outside San Francisco and near to Stanford University.

Eighty-one percent of Bethesda's adults hold bachelor's degrees, as do 79 percent in Palo Alto. Roughly half of the adults in both communities went on to earn advanced degrees as well.

Stanford is No. 1 on 10-to-50K list

Stanford University is one of America's most prestigious institutions of higher learning. It's No. 5 in U.S. News and World Report's current rankings of the nation's best universities.

But its namesake community has done even better. Stanford, Calif., is No. 1 in On Numbers' rankings of the smartest places with populations between 10,000 and 49,999.

Stanford — the community, not the university - is a census designated place (CDP) with 13,700 residents.

CDPs are unincorporated communities that have the characteristics of cities, as determined by the U.S. Census Bureau.

Fully 90.7 percent of Stanford's adults (25 or older) hold bachelor's degrees, compared to the national average of 27.5 percent.

Nearly two-thirds of those same Stanford residents have also gone on to earn graduate or professional degrees.

Two upscale suburbs hold the next two slots in the 10,000-to-49,999 brainpower standings: Scarsdale, N.Y., and Winnetka, Ill.

The state with the most entries among the top 50 is California with 10, followed by Illinois and Virginia with six apiece.

Chevy Chase leads small communities

Chevy Chase Village, Md. - population: 2,000 - is a very small community. It's also very smart.

Nearly two-thirds of the adults in the tiny Washington suburb hold graduate degrees, pushing Chevy Chase Village into first place in On Numbers' brainpower rankings for places with 1,000 to 9,999 residents.

The runners-up are nearby Somerset, Md., and Shorewood Hills, Wis., a suburb of Madison.

The breakdown for Chevy Chase Village shows that 63.9 percent of its adults hold advanced degrees and another 28.9 percent stopped after earning bachelor's degrees. That adds up to 92.8 percent who graduated from four-year colleges. (The comparable national figure is 27.5 percent.)

New York, with 14, is the state with the most communities among the top 50 on the list of small places. Maryland is next with eight, and California and Texas have six each.