- In the Middle Colonies of New Jersey, New York, and Pennsylvania, counties were important units of government, but they also contained townships (towns in New York), that had varying degrees of recognition and significance for some local governmental functions.
These three systems of local government continued beyond the colonial period and became embodied in State constitutions and legislative acts. The 1790 census reported data for 292 counties. As the Nation expanded westward, the county form of local government followed; thus, the nineteenth century was the most active period of county formation (see Table 4-2).
Table 4-2. Number of Counties and Parishes in Early Decennial Censuses
| Decennial Census | Number of Counties and Parishes |
|---|---|
| 1790 | 0,292 |
| 1850 | 1,621 |
| 1870 | 2,247 |
| 1900 | 2,713 |
| 1920 | 3,041 |
The totals do not include statistical equivalents of counties (such as the independent cities of St. Louis and Baltimore and the cities of Virginia, some of which were independent as early as 1850).
The Northwest Ordinance provided for the establishment of local government in the newly settled territories, which later would become States. It empowered the territorial governors to create geographic divisions, which subsequently could serve as constituent units for representation in the territorial assembly. Legislators in the territories and new States usually laid out counties for the entire area of the jurisdiction. As a result, when new States gained admission to the Union, they often already had counties, although the less-settled portions of the State might have only a few very large counties, which would subsequently be subdivided as settlement expanded.
The process of county formation continued actively into the first two decades of the twentieth century. The largest single increase occurred in 1907
