HARRISBURG -- Stark population losses in Western Pennsylvania will likely make the region a target for adjustments as reapportionment begins in the state Capitol.
Of the 10 House districts that lost the greatest number of residents over the last decade, seven are in Allegheny County. Another two are in Fayette County, with the final district in Philadelphia.
The state Senate districts with the highest losses also tilt west: The top three are in Allegheny County, followed by Beaver and Fayette.
Top lawmakers involved with the reapportionment process say it's too early to say what that shift in population will mean for the number of western districts. Observers note that the decreases continue a lengthy pattern that resulted in three House seats moving east in the last round in 2001.
The actual process of drawing those lines begins now, with the Legislative Reapportionment Commission on Tuesday approving the necessary census data. That panel has 90 days to craft preliminary maps, which will then be available for public comment.
The five-member commission will tweak boundaries for the 203 state House of Representatives seats and 50 state Senate districts. Congressional districts, which are crafted using the same census data, are formed separately, through legislation also to be approved this fall.
Made up of legislative leaders, that panel's geography also has an Allegheny slant: House Majority Leader Mike Turzai, House Minority Leader Frank Dermody and Senate Minority Leader Jay Costa are all members, as well as Senate Majority Leader Dominic Pileggi, R-Delaware.
It is chaired by Stephen J. McEwen, a former president judge of Superior Court and ex-Delaware County district attorney.
As those members review which districts have seen the most dramatic population changes since the 2000 census and ensuing 2001 reapportionment, Mr. Costa's district will be high on that list.
The top Senate Democrat saw his district shrink to its current 227,651 residents, down from 243,119. That decrease of 15,468 constituents was the third-largest drop in any Senate district.
Sen. Jim Ferlo, a Highland Park Democrat, had the largest decrease, now representing 25,495 fewer Pennsylvanians than when he joined the Senate in 2001.
In the state House, the top three districts to lose population were all in Allegheny County and all currently held by Democrats. Rep. Joe Preston's East Liberty district lost 10,758 residents, followed by Rep. Marc Gergely of White Oak's loss of 6,766 and Rep. Jake Wheatley of the Hill District losing 6,460.
Among both chambers, gains were generally seen in the Lehigh Valley, southeast and south-central portions of the state.
"Certain parts of the west have [lost population], but not all parts of the west have," said Mr. Turzai, R-Bradford Woods. "Butler County has had growth actually, and I believe even northern Allegheny has had growth."
In fact, Mr. Turzai's district grew by more than 10 percent, adding 6,515 since the last census.
"Some districts have to get larger, some districts have to get smaller, and as a result there may be some shifts within the state," he said. "Those are decisions that the commission is going to have to address."
Historically, addressing those changes has meant that seats move from the southwest to the east, said G. Terry Madonna, a political scientist at Franklin & Marshall College in Lancaster. He noted that was the case for three seats in 2001, with another moving from Philadelphia to the northeastern county of Monroe.
Mr. Madonna estimated that could be the case again for "a minimum of one, and maybe more."
Not all districts changed dramatically. One with the least upheaval was that of Republican Rep. Matt Baker, whose Tioga County district grew by only 27 people, a population shift of 0.04 percent.
But calculating the changes in population is the easy part. Sorting out how to redraw district lines in a fair manner gets complicated quickly.
The district numbers will be compared with a target population figure to help determine which are too big or too small. For the House, that number is 62,573, and for the Senate, 254,048 people. Both figures are larger than in 2001, given the state's population growth.
Mr. Madonna said local issues, including the breakdown between majority and minority demographics and whether a district is "compact and contiguous," have to be taken into account as well.
Democrats on the panel also raised questions about local boundaries Tuesday, pointing to some precinct boundaries that they say don't match the way counties have traditionally divided their voting districts.
Republicans said some minor issues are typical and will be worked out during the process, but they may have some help from the public as well. All of the data they're using will be available online at www.redistricting.state.pa.us, starting today, along with information on upcoming public hearings.
Laura Olson: email@example.com or 717-787-4254.