The Pennsylvania State Route Numbering
Early Numbering Systems
The old Pennsylvania Department of Highways and the current Department
of Transportation have simultaneously employed various versions of
two simultaneous numbering systems. First, state-maintained highways
were given legislative numbers in 1911, and these were renumbered
according to a new system in the 1980s. These numbers are reference
numbers that were and are useful for bookkeeping and documenting the
state highways. Second, a visible, more user-friendly system was developed
in 1925 (and revamped in 1928 and in later years) for the driving
public. This system originally encompassed the signed state routes
1-999, but included the US highway system in 1928 and the Interstate
highway system decades later.
The Original 1911 System (Internal Use)
The original system, begun on May 31, 1911 under the Sproul
Road Bill, assigned sequential numbers to short segments of state
roads, covering numbers as high as the 300s by 1925. These highways
and their numbers were found on road maps of the 1911-1925 era with
designations such as State Highway No. 244. The numbers became the
legislative route (LR) numbers that were used until the SR system
was effected in the 1980s. By its last few years, the numbering system
had three subsystems:
- Sequentially numbered routes · Routes numbered 1,
2, ... to numbers in the low 1000s. These routes were the only ones
in existence until 1925, when the signed state routes were established.
In 1925, the majority of the signed state routes (which had their
own numbering system; see below) followed these sequentially numbered
routes. Later on, signed state routes still mainly followed these
low-numbered LRs but commonly followed the high-numbered ones or
- County-based routes · Many five-digit routes were
established with numberes decided according to the county. The 67
county names were alphabetized, and Philadelphia County was excluded
from the list. The remaining counties were numbered 01 (Adams County)
to 66 (York County), and these county codes were used as the first
two digits of the five-digit county routes. The remaining three
digits were used to distinguish the different five-digit routes
within a county.
The New 1925 System (Public Use)
The 1925 system established the signed routes numbered especially
for travellers. The system assigned one-digit numbers and a few two-digit
numbers to major highways ("auto trails") across the state,
with even numbers assigned to north-south routes and odd numbers assigned
to east-west routes. The route numbers increased from east to west
(2 near New Jersey, 8 near Ohio) and from south to north (1 near Maryland,
9 near Lake Erie). The 1911 LR numbers remained as an internal referencing
system. The 1925 system was envisioned in 1924, but probably was not
noted on maps until the following year. The system began by numbering
nine auto trails that were far better known by name:
||West Virginia to New Jersey via Pittsburgh and
Philadelphia; now mainly US 30 west of Philadelphia and US 1 to
||New York to Philadelphia via Scranton and Easton;
now mainly US 1 north of Scranton and PA 611 to the south
||William Penn Highway
||West Virginia to New Jersey via Pittsburgh,
Harrisburg, and Allentown; now US 22, US 322, US 422, US 222, and
US 22 from west to east.
||New York to Maryland via Williamsport, Harrisburg,
and York; now mainly US 15, I-180, US 11/US 15, and I-83 from north
||Erie to Philadelphia via Meadville and Harrisburg;
now mainly PA 97, US 322, and PA 3 from northwest to southeast.
||Waterford to New York via Mansfield and Scranton;
now mainly US 6.
||Chicago-Buffalo Highway, Yellowstone Trail
||Via Erie; now US 20
||National Old Trails Road
|Maryland to West Virginia via Uniontown and
Washington; now US 40..
||Portland to Maryland via Bethlehem and Philadelphia;
now PA 512, PA 378, PA 309, and US 1 from north to south.
Other auto trails were also numbered shortly thereafter. By 1926,
the following auto trails were included.
||Old Monument Trail
||Bradford to Grantsville via Dubois and Johnstown;
now mainly US 219.
||William Flinn Highway
||Erie to Morgantown via Pittsburgh, now mainly
US 19 and PA 8.
||Highway from Chambersburg to Philadelphia
||Via Harrisburg; now mainly US 11, US 322, and
US 422 from west to east.
||Highway from Scranton to Lewistown
||Via Sunbury; now mainly US 11 east of Selinsgrove
and US 522 to the west.
||Monticello, NY to Wilkes-Barre via Honesdale
and Scranton; now mainly PA 652, US 6, and US 11.
||Via Frederick and Gettysburg; now mainly US
||Highway from Reading to Harrisburg
||Via Lancaster, now mainly US 222 and PA 230
from east to west.
More auto trails were numbered by 1928, including:
||York to Baltimore via Red Lion and Stewartstown;
now mainly PA 24
||Benjamin Franklin Highway
||New Castle to Ebensburg via Kittanning, and
Harrisburg to Philadelphia via Reading; now mainly US 422
||Erie to Beaver Falls via Greenville and New
Castle; now mainly PA 18
||Wilkes-Barre to Philadelphia via White Haven
and Allentown; now mainly PA 309
||Lykens Valley Trail
||Millersburg to Stroudsburg via Pottsville and
Lehighton; now mainly US 209
||Mount Union to Emmitsburg via McConnellsburg;
now mainly US 522 and PA 16
||Bradford Farmers' Valley Highway
||Bradford to Smethport; now PA 46
||Lock Haven to Ridgway via Renovo and Saint Marys;
now mainly PA 120
|Now mainly US 220 south of Williamsport.
||Fentonville, NY to Smithfield via Warren, Kittanning,
and Uniontown; now mainly US 62, PA 66, and US 119
||Erie to Pittsburgh via Meadville and Mercer;
now mainly US 19
By 1927, the numbering system was expanded to include more
two-digit numbers beyond the ones listed above. Two-digit numbers
were typically assigned to branches off the single-digit routes so
that the ones digits of the branches matched the single-digit numbers.
For example, 58 and 98 were branches off 8. Other two-digit numbers
are not branches but were located near the associated one-digit route.
Many two-digit numbers were used more than once at this time, perhaps
with the plan of eventually connecting some of them together. Three-digit
numbers were not assigned.
A scan of a 1927
road map is available on Harold Cramer's Maps
of PA site. Auto trails from across the country are listed on
Dave Schul's North
American Auto Trails web site.
[More information to come on the 1925 system.]
The 1926 US Highway System (Public Use)
In 1926-27, the US highway system was implemented. This system
assigned a new set of numbers that did not change when roads crossed
state boundaries, setting up the nation's first interstate highway
system. (Here "interstate" indicates a system extending
across the country and does not refer to the system of Interstate
superhighways built decades later). The major state routes, and some
minor state routes, were assigned the new US numbers, but not entirely
to Pennsylvania's liking. While some of the major highways that had
been first numbered in 1924-26 were given one US highway number (e.g.,
Roosevelt Highway/7 became US 6), others were given several numbers
(e.g., 4 became US 111 south of Harrisburg, US 11 from Harrisburg
to Northumberland, US 120 from Northumberland to Williamsport, and
US 111 north of Williamsport). Pennsylvania would have preferred a
single number along its designated major highways, and so left the
state route numbers signed while adding the US highway numbers. The
Roosevelt highway, for example, became US 6/PA 7 (dually signed),
while the Susquehanna Trail became US 111/PA 4, US 11/PA 4, US 120/PA
4, and US 111/PA 4 (in addition to any numbers from overlapping major
highways, such as the William Penn Highway, US 22/3) so that PA 4
could be followed along the entire Susquehanna Trail.
The Modern 1928 System (Public Use)
In 1928, the "modern" state route numbering system
was implemented. After several of the US highway system's initial
flaws were corrected in its first two years (an interesting combination
of renumberings and relocations, including US 19, US 22, US 120, US
422, and more) and that system seemed more finalized, Pennsylvania
decided to revamp its state route numbering system. The US system
used a parent-child system, where main "parent" routes were
given one- and two-digit numbers, and branch or "child"
routes of those routes were given three-digit numbers whose last two
digits matched the parent. (Note that this system paralleled the 1925
state route system, also a parent-child system, where two-digit routes
were branches off the one-digit routes, and the last digit matched.)
The new state route system established one- and two-digit parent routes
in a style similar but opposite to those of the US highway system.
Two-digit odd numbers were assigned to east-west routes, and even
numbers assigned to north-south routes, the reverse of the US highway
system. The new state route system also established both child (101-799)
and spur routes (800-999), which were given three-digit numbers based
on the connecting parent route. When this 1928 system was implemented,
many of the earlier numbers were changed.
Several of the named trans-state highways kept their numbers from
1925: 1 (duplicated US 1), 2, 3, 4, 5, 7, 8, 9, 12, 17, and 41. Others
were renumbered to avoid duplication with US highway numbers (6 became
10 and 60, 11 became 81, 13 became 17 and 33, and 19 became 39). PA
1 may have remained because its child routes (101-701) would not duplicate
any US highway numbers, and nearly all of PA 1 also had a US highway
number that eventually replaced it (US 30 and US 1). Additionally,
the sixteenth trans-state highway, 24, became part of 14, and 24 was
reassigned to the east.
The Interstate Highway System (Public Use)
The Eisenhower Interstate Highway System was developed in the 1950s
and mostly completed by 1980. This system of high-speed freeways (limited-access
highways) replaced almost all at-grade intersections with interchanges
and allowed nearly uninterrupted travel across the country. This system
supplemented the long-established state and US highway systems.
The 1980s State Route System (Internal Use)
The State Route (SR) system replaced the internal LR system of 1911,
which suffered from the peculiarity that many routes had vastly different
internal (LR) and external (PA, US, I) numbers, and often a signed,
externally numbered route would change LR numbers several times. The
SR system assigned one-, two-, and three-digit numbers to the signed
routes so that the internal and external routes matched in almost
every case. For example, PA 235 became SR 235, or since all the SRs
are often written consistently as four-digit numbers with padded zeroes,
PA 235's SR may also be written as SR 0235. These SR numbers extend
along the entire length of almost all signed state, US, and Interstate
routes. Additionally, all other state-maintained roads, such as secondary
roads, interchange ramps, truck escape ramps, and rest areas, were
given four-digit numbers above 1000. The SR numbers above 1000 are
specific to each county, and one can find SR 1001, SR 1002, and other
low-numbered such SR routes in all 67 counties, including Philadelphia.
SR numbers and their segment numbers can be found on little white
signs along SR routes.
This rest of this web site will give a general overview to the numbering
systems used in Pennsylvania since 1928, with plenty
of examples. This site also provides a detailed look at how each of
the approximately 900 routes (past and present) fit (or do not fit)
into the numbering systems.
If you wish to follow along with a couple of road maps, I would suggest
downloading the latest
PENNDOT map and browsing the 1929 map available online at Bruce
Harper's site in three pieces (west,
Continue to Parent Routes
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