This list generally refers only to the population of individual urban places within their defined limits at the time of the indicated census. Some of these places have since been annexed or merged into other cities. Other places may have expanded their borders due to such annexation or consolidation. For example, after the 1898 consolidation of New York City, the Census Bureau has defined all the boroughs within its city limits as one "urban place". Similarly, Philadelphia's population has included the census counts within both the former urban areas of Northern Liberties, Pennsylvania and Southwark, Pennsylvania ever since Philadelphia's 1854 consolidation.