The Keystone Markers consist of a sign and a pole. Signs and poles are historically of cast iron construction and were painted a standardized Pennsylvania blue and gold or blue and yellow. Variations in color were due mainly to fading. See the slideshow for more information.
SIGN TYPES: As shown in the first photo below, there are four types of signs--two standard shapes and two variants.
- Front Mount, Single Face Standard Keystone: Shown by the Blue Ball marker in the first photo below, this is the type most commonly used for cities, towns, and villages. The sign is printed on one side only and mounts on the Front Mount Pole. It has a ball finial on top, usually painted blue. On most markers, the ball finial is a separate piece held in place in the pole with set screw. We have observed there are two types of applied ball finials, one with a thick collar and one with a thin collar. Some markers hae lost their ball finials to time. Some front mount markers did not have a separately-applied ball finial but instead had a ball finial cast integrally with the pole. This front-mount Keystone-shaped sign was also used for "Traffic" signs, such as "School Zone," "Dangerous Hill," and other such messages. These can be viewed under "T" in the Find A Marker" section of this website. Others were used as "Directional" signs (look under "D") and still others to denote an historic place/event (look under "H" in the Find A Marker section.
- Top Mount Dual Face Standard Keystone: Shown by the Little Pine Creek marker in the photo, this type is most commonly used for rivers, creeks, etc. The sign is printed on both sides and is mounted on the Top Mount Pole. Note the webbing at the base of the sign where it meets the pole. The many of these that we know of are shown under "S" for Stream in the Find A Marker section.
- Keystone Variants: There are at least two variations of the keystone shape, shown in here by the Looker Mountain Trail sign and the Marguerite directional sign. The Looker Mountain keystone shape was also used to denote borough boundaries. It is likely all variants used the Front Mount Pole.
- Large Ridgetop Keystones: Locations where the major highways crossed ridgetops were typically marked with large wooden versions of the Keystones, giving the name of the mountain and the elevation above sea level. These were found along the "National Pike" (U.S. Route 40), the "Lincoln Highway" (U.S. Route 30), the "Roosevelt Highway" (U.S. Route 6), the "Susquehanna Trail (U.S. Route 15), and the "Lakes To Sea Highway") which followed a number of different routes from Erie PA to Philadelphia (then on to Atlantic City in New Jersey). Look under "L" for "Large" in the Find A Marker index.
POLE TYPES: There are two pole types.
One is a front-mount pole, with the keystone sign mounted in front of the pole. See the Blue Ball marker below for an example. The other type is a top-mount pole, with the keystone (often a dual face variety) mounted on top. See the Youghiogheny River and Tunkhannock Creek markers below for examples.
Click an image below for more detailed information: