Allegheny County and most of the metropolitan region show continued trends of modest population loss, according to the latest estimates from the U.S. Census Bureau.

The bureau reported yesterday that the county's population was estimated at 1,223,411 as of July 1, 2006, a drop of 9,625 from the year before and 58,255 from the last formal census head count in 2000.

Allegheny remained the 30th largest county in the nation. Wayne County in Michigan and Cook County in Illinois showed bigger population losses in the past year than Allegheny, according to the estimates, but only Wayne had a more severe percentage loss of residents.

Within the seven-county metropolitan region, only Butler County showed any significant population increase between 2005 and 2006, a net gain of 1,375, to 182,901. Washington gained an estimated 14 residents, to 206,432.

Other counties losing population were Armstrong, down 431 to 70.096; Beaver, down 1,089 to 175,736; Fayette, down 446 to 145,760; and Westmoreland, down 693 to 366,440.

The Pittsburgh metro area's population was estimated at 2,370,776, down 10,895 from 2005 and 60,309 from the year 2000, with Allegheny's net loss representing most of the decline in both cases.

All of the counties except Butler have more deaths than births occurring on an annual basis, and only Washington has been able to make that up with more people moving in than moving out.