Also topping the list were Salt Lake City, Phoenix and Raleigh, N.C.
Growth in San Francisco, Seattle and New York, which have some of the largest numbers of home Internet users total, is leveling off because those markets are more saturated relative to other metropolitan areas, said Jarvis Mack, a senior media analyst at Nielsen/NetRatings.
"Now we're starting to see other urban centers catch up," Mack said.
The number of home Internet users in the San Francisco Bay Area actually fell 8 percent last year to 2.8 million. The exodus of dot-commers who were laid off is the most likely cause of the drop, Mack said.
Neighboring Los Angeles may have absorbed some of the Internet surfing contingent from the Bay Area, Mack said. It is second only to New York City in total number of people using the Net from home, counting 5.7 million, up 10.5 percent from a year ago.
Mack attributed the expanding Internet surfing population in Phoenix, also one of the fastest-growing cities in the nation, to a larger number of retirees using the Internet. The Winter Olympics, which will be covered extensively online, may be fueling demand for Internet access in Salt Lake City, he said.
The total U.S. Internet population rose 6 percent last year, to 104.8 million, according to Nielsen/NetRatings. The rate of expansion has slowed compared with the late '90s, said Mack, when the Internet boom and a proliferation of free Internet service providers drove double-digit growth.
Though free Internet access has largely disappeared along with the dot-com bubble, Mack believes a few areas remain ripe for rising numbers of Internet customers, particularly Midwest cities like Cincinnati and St. Louis.
Nielsen/NetRatings conducted its study through interviews with 68,000 home Internet users across the country.