Question: How long is the route that connects Philadelphia to Lehigh County?

Context articles: Pennsylvania Route 145
Pennsylvania Route 873
Lynn Township, Lehigh County, Pennsylvania
Haines Mill
Pennsylvania Route 309
Allentown, Pennsylvania
Carbon Lehigh Intermediate Unit
Pennsylvania Route 863
Lehigh County Historical Society
Coplay Cement Company Kilns

Pennsylvania Route 145 (PA 145) is a 20.89 mi long north–south state highway in the Lehigh Valley area of eastern Pennsylvania.
 It connects Interstate 78 (I-78) and PA 309 in Lanark, Lehigh County to PA 248 in Weiders Crossing, Northampton County.
 PA 145 is the main north-south arterial into Allentown, the third-largest city in the state.
 The route enters the city on South 4th Street and follows multiple streets to downtown, where it follows the one-way pair of 6th Street northbound and 7th Street southbound.
 North of Allentown in Whitehall Township, a seven-mile (11.2 km) portion of PA 145 is known as MacArthur Road, named in honor of General Douglas MacArthur.
 MacArthur Road is a divided highway; between U.S. Route 22 (US 22) and Eberhart Road, it is six lanes wide with a Jersey barrier and jughandles while the remainder of the road a four-lane divided highway.
 MacArthur Road is the location of the main commercial center of the Lehigh Valley.
 North of Eagle Point, PA 145 becomes a two-lane undivided road that parallels the Lehigh River, crossing the river into Northampton County at Treichlers.
 The route continues along the east bank of the river and passes through Walnutport before reaching its northern terminus.
 PA 145 is dedicated as the Battle of the Bulge Veterans Memorial Highway in honor of the veterans who fought in the Battle of the Bulge.
Pennsylvania Route 873 (PA 873) is a north-south, two-lane road mainly located in northern Lehigh County, Pennsylvania with a small section in Northampton County.
 Its southern terminus is at PA 309 in Schnecksville.
 Its northern terminus is at PA 248 in the Lehigh Township hamlet of Weiders Crossing.
 The route runs through rural areas in northern Lehigh County, intersecting the western terminus of PA 329 in Neffs.
 PA 873 passes through Slatington as Main Street before it crosses the Lehigh River into Northampton County and immediately reaches its northern terminus south of Lehigh Gap in Blue Mountain.
Lynn Township is a township in Lehigh County, Pennsylvania, in the United States.
 It is a suburb of Allentown, Pennsylvania, in the Lehigh Valley region of the state.
 The largest township by area in Lehigh County, it is the most rural and least densely populated township in the county.
Haines Mill, also known as Haines Mill Museum, is a historic grist mill located at South Whitehall Township, Lehigh County, Pennsylvania.
 It was built about 1840, and is a four-story, stone building with a slate covered gambrel roof.
 It is three bay by three bay, 42 feet by 46 feet, 9 inches.
 The interior was rebuilt after a disastrous fire in 1908.
 A three-story brick addition was built in 1930, with a lean-to roof.
 Atop the main roof is a cupola.
 It remained in full operation until 1957.
 Today, Haines Mill is operated as a partnership between the County of Lehigh, which owns and maintains the site, and the Lehigh County Historical Society, which provides public tours.
Pennsylvania Route 309 (PA 309) is a major highway which runs for 134 miles (216 km) through Pennsylvania in the United States.
 The route runs from the interchange between PA 611 and Cheltenham Avenue on the border of Philadelphia and Cheltenham Township north to an intersection with PA 29 in Bowman Creek, a village in Monroe Township, Wyoming County.
 It connects Philadelphia and its northern suburbs to Allentown, Hazleton, and Wilkes-Barre.
 A limited-access highway portion of PA 309 in the Wilkes-Barre area is known as the North Cross Valley Expressway.
 A limited-access highway portion of PA 309 in Montgomery County is known as the Fort Washington Expressway.
 PA 309 parallels the newer Interstates 476 and 81 for much of its length.
Allentown (Pennsylvania Dutch: "Allenschteddel") is a city located in Lehigh County, Pennsylvania, United States.
 It is Pennsylvania's third most populous city and the 224th largest city in the United States.
 As of the 2010 census, the city had a total population of 118,032 and is currently the fastest growing city in all of Pennsylvania.
 It is the largest city in the metropolitan area known as the Lehigh Valley, which had a population of 821,623 residents as of 2010 .
 Allentown constitutes a portion of the New York City Combined Statistical Area and is the county seat of Lehigh County.
 In 2012, the city celebrated the 250th anniversary of its founding in 1762.
Carbon Lehigh Intermediate Unit #21 (CLIU), located in Schnecksville, Pennsylvania, Lehigh County USA, is one of twenty nine Intermediate Unit Educational Service Agencies created by an Act of the General Assembly of Pennsylvania in 1971.
 CLIU provides services to 14 public school districts, non-public schools in its service region and two Vocational-Technical schools in Carbon County and Lehigh County.
 The agency has no taxing power.
 Its revenues come come: federal grants, state grants, private grants, annual payments from each public school district in its region and charges to individuals for some services like driver's education.
 The agency provides many services including specialized special education services and training for teachers to meet their state mandated continuing professional education with some offered online.
 CLIU21 also operates a Librarians' Consortium for librarians from public libraries, private libraries, school libraries and higher education librarians.
Pennsylvania Route 863 (PA 863) is a state highway in Lehigh County, Pennsylvania.
 The route runs 13.99 mi from U.S. Route 222 (US 222) in Upper Macungie Township north to PA 143 in Lynn Township.
 The route is a two-lane undivided road that runs southeast-northwest through rural areas in western Lehigh County.
 Along the way, PA 863 has an interchange with Interstate 78 (I-78)/US 22 in Weisenberg Township.
 The road was originally unpaved, being improved to a bituminous road by the 1940s and a paved road by 1950.
 PA 863 was designated in the 1960s.
Lehigh County Historical Society is a nonprofit organization, founded in 1904, dedicated to collecting, preserving, and exhibiting the history of Lehigh County, Pennsylvania and the Lehigh Valley.
 The Historical Society and Lehigh Valley Heritage Museum are located at 432 West Walnut Street in Allentown.
Coplay Cement Company Kilns, also known as the Saylor Park Industrial Museum, is an open-air historic site located at Coplay, Lehigh County, Pennsylvania.
 The nine kilns were built in 1892-1893, and used for the production of Portland cement.
 They are constructed of locally produced red brick, and are known as Schoefer vertical kilns.
 They were shut down in 1904.
 The Coplay Cement Company donated the kilns and surrounding land to Lehigh County in 1975, for a cement industry museum.
 It is operated as a partnership between the County of Lehigh, which owns and maintains the site, and the Lehigh County Historical Society, which provides educational services.
 It was added to the National Register of Historic Places in 1980.