Politically speaking, Pennsylvania has been described as having the Democratic strongholds of Philadelphia in the east and Pittsburgh in the west and the equivalent of conservative Alabama in between. But in the border region between these two politically polar areas lies one of the most competitive Congressional districts in the nation, the 6th District in suburban Philly.

The district, running from the posh suburbs in Lower Merion Township to the exurbs of Norristown and the faltering factory town of Reading, was created before the 2002 midterm election by largely Republican redistricting officials with the idea of ensuring a new GOP vote in the House. But only four years after carving the district out, the growing suburban sprawl of Philadelphia coupled with the unpopularity of President Bush has made this one of the races to watch as Democratic strategists try to cobble together a possible majority in Congress.

The region that now makes up the 6th District started out as a key transportation and manufacturing stop as the industrial revolution marched west out of Philadelphia and much needed raw materials like coal and produce moved east from the central and western parts of the state. The Reading Line and Main Line railroads helped spark the growth of cities along the way such as Reading and Pottstown.

The district also is home to locations of historic and educational significance. Valley Forge, where George Washington's embattled troops spent six long months from December 1777 to June 1778 during the Revolutionary War, lies along the eastern edge of the district. Some 12 universities, including Bryn Mawr, Kutztown and St. Joseph's, and three community colleges dot the region.

Closer in to Philadelphia, the towns of Ardmore and areas in Montgomery County would become some of the earliest and wealthiest suburbs in the region. The wealthy philanthropist Lenore Annenberg calls the Lower Merion Township home and throughout the southeastern section of the district, a growing suburban voter base has helped push the district further towards the Democratic Party.

This spread of the suburban voter has been one of the key factors in the shift in voting patterns among residents in the 6th. Throughout the 1990s the decay in manufacturing and traditional blue collar, so-called Reagan Republican jobs lead the region further and further left. By 2000, the area narrowly voted for Al Gore.

The region is now seen as a critical district for both Congressional and statewide campaigns.

"[I]f the Republicans cannot win those [suburban] counties, they cannot win statewide in Pennsylvania," said G. Terry Madonna, director of Franklin and Marshall College's Center for Politics and Public Affairs. "The other element in the Philadelphia suburbs is that is where the largest number of undecideds or I should say swing voters live... It's ground zero in the campaign."

In 2002, in the newly formed 6th District's first Congressional contest, Republican State Sen. Jim Gerlach battled the son of former Sen. Harris Wofford. The race was far closer than the conceivers of the district intended and Gerlach squeaked into office by 5,500 votes out of 200,000 cast.

2004 showed how the district continued to slip towards the Democrats, with Sen. John Kerry beating President Bush 51 - 48 percent. Gerlach was one of the few Republicans seen as vulnerable and both Republican and Democratic national supporters poured into the district. Gerlach again edged out his competitor attorney Lois Murphy, but only after outspending her $2.2 million to $1.9 million.

The district has continued to skew Democratic on many national issues, including a growing opposition to the war in Iraq, support for abortion rights and environmental issues.

After two elections, Gerlach should be safe -- but he's not and analysts have said the rematch in 2006 with Murphy will likely be one of the most competitive in the nation.

"There are a number of key races around the country. The eyes of the nation will be on this election on that evening in November. The majority of the House of Representatives may rest pretty much on this race," Sen. John McCain, R-Ariz., said as he campaigned for Gerlach in July.

-- Compiled by Lee Banville for the Online NewsHour