This page contains information specific to Pennsylvania. For additional information about the project, please see also the project About page.
Incorporation events for all known boroughs, cities, and towns, along with all known home rule charter, optional charter, and optional plan adoptions, have been identified. Well over 95% of these events include primary source citations. Further, over 95% of current boroughs and cities have primary source citations for actions granting them the power to operate under the Borough Code or the Third Class City Code, respectively, in lieu of a legislative special charter. It is likely that over 90% of boundary changes to boroughs and cities from 1871 through 1974 have been identified. Annexations before 1871 may only be contained in municipal records, and are more likely to remain unidentified. Boundary changes after 1974 are also more likely to remain unidentified, in part due to the large increase in the volume of court records, in part due to confusion as to the court division in which these matters were to be filed, in part due to the difficulty of finding cases of this nature in the Common Pleas Case Management System (CPCMS) because of its focus on criminal matters, and in part due to both the lack of statutory guidance and the higher likelihood of improvident records disposition actions for annexation referenda only filed with the county board of elections.
All known townships have had a preliminary review to identify the probable formation date. Counties in Southeastern Pennsylvania formed prior to 1750 have mostly had detailed review of either road dockets or county commissioner minutes to determine when a township first had officers or taxes assessed. In most other counties, primary source citations for township formations and boundary changes may only be available when entered in the same court dockets as borough, city, and town events, and may be limited to after 1850. Often, court dockets may leave out key information, such as when or whether an action was finally approved, or may omit township formation events altogether. In these cases, court papers have only been examined in any detail in a limited number of counties.
Special thanks to Tom Yoset, of Meadville, Pa., for allowing me to incorporate his Crawford County Historical Borough Boundaries and Historical Township Boundaries pages into this resource, and for his wealth of knowledge on the county's records.
Plaudits are also given to the information professionals at the State Archives of Pennsylvania and State Library of Pennsylvania, who have gone above and beyond to provide the highest levels of access to their records despite ongoing budget cuts and renovations. Many thanks also to the many other municipal, county, and state officials who have opened their records for this project.
At the outset, the project's scope was limited to one county. The Recorder of Deeds's Charter Index and the Clerk of Courts's Miscellaneous Index were examined to locate pertinent matters. Court dockets were also reviewed both to locate pertinent matters and abstract relevant facts. Codes of ordinances for municipalities were examined for references to annexations, and ordinances were examined in a number of borough halls. Where records were missing or incomplete but references to boundary changes were found either in county records or published county histories, newspapers were consulted for copies of legal notices and general articles concerning court actions. Historical state codes were examined to determine the legal procedures and the agencies involved in such matters. A database was created to organize the information in a standardized fashion.
The scope of the project was expanded statewide, prioritizing boroughs and cities over townships, and prioritizing later events over newer. Geographic changes notes in published U.S. Census Bureau reports were transcribed from 1870 through the present, and pertinent information was abstracted into the database. Later, U.S. Census Bureau correspondence with municipal engineers and secretaries, which formed the basis for many of the notes, were examined and abstracted in part. Several counties surrounding the pilot county were also visited, also initially examining the Recorder of Deeds's Charter Index, some dockets held by the Clerk of Courts, and municipal codes held by county law libraries.
While there is no statewide record series covering all boundary changes, several state agency record series primarily covering the mid-20th Century were examined in detail, including Department of Education annexation files stored at the agency and the State Archives, along with Department of Community and Economic Development boundary change files. Later, home rule and optional plan files were also reviewed both at that department and at the Legislative Reference Bureau. Municipal codes at the State Library and available online were examined. An extract of Department of State Corporation Bureau records concerning boroughs was obtained, and pertinent filings in their "Orphan" microfilm collection containing microfilmed charter records from county Recorder of Deeds were examined.Separately, portions of local legislation indexes by Calvin G. Beitel and Giles D. Price were converted into database tables and linked with auto-generated statute links. Acts incorporating boroughs and cities were located and abstracted from this data, with review of acts amending charters ongoing. Work Projects Administration compilations concerning municipal incorporation and boundaries were examined where available -- these are found in part in microfilmed files at the State Archives; in part in published inventories of county archives; and in part by happenstance at the county level, normally at the Recorder of Deeds or the Tax Assessment Office.
The remaining counties were also visited. In many counties, county histories were also referenced. Most counties do not maintain comprehensive indexes to Clerk of Courts records, necessitating a docket by docket search for pertinent cases. In most cases, pertinent court dockets from 1850 through 1975 have been reviewed.
Rather than routinely visit borough and city halls, as had been done in the pilot county, written requests were made on the basis of references found in reviewed U.S. Census Bureau records, municipal codes, and, in some cases, county records. In-person municipal hall visits were limited to situations where large amounts of records were involved, or where missing information or discrepancies required a more thorough examination of records.
Over time, other record series at the state level, such as appellate court dockets, reporters, and paper books, along with portions of the Land Office Map Collection, were examined. In order to fill in township formation dates that have not yet been researched in county records, a 1965 Department of Internal Affairs publication containing incorporation dates was digitized and abstracted. U.S. Census Bureau enumeration district maps at the National Archives were also examined both as a rich source of mid-20th Century maps, as well as to evaluate discrepancies between U.S. Census Bureau reports and local government records. Additional maps available at the Library of Congress and repositories throughout Pennsylvania have also been examined.
U.S. Census Bureau TIGER/Line Shapefiles, 2012 vintage, were used to create the initial GIS base layer. Municipal boundaries were derived from the County Subdivision layer, and ward boundaries in Philadelphia were derived from the Voting Districts layer. Multipolygon features were split into polygon features, and data was converted to WGS 84 (EPSG:4326). In order to show changes in boundaries, features were further split into "areas" that share a common jurisdictional history, mostly based on data taken from boundary legal descriptions.
Accuracy of the source GIS data varies widely throughout Pennsylvania. Efforts have been made to conflate data to match the 2019 vintage where the latter is more accurate or precise. In some cases, minor adjustments derived from alternate sources were made to municipal boundaries. Most of these adjustments were made after reviewing maps and primary source records described above in conjunction with other modern sources, such as, but not limited to: authoritative municipal maps (principally zoning maps); county tax assessment maps, parcel records, and, where accessible, GIS data (both municipal boundary and parcel layers); municipal boundary data compiled by the PAMAP Program in 2007; and PennDOT's Pennsylvania Municipal Boundary GIS layer.