Today’s Delaware counties did not always exist in the present form. They went through many different changes in the space of a few short years.

Delaware Colony Counties

Following the English conquest of 1664, all of the land on the western side of the Delaware River and Delaware Bay was governed as part of the New York Colony and administered from the town of New Castle.

During the brief recapture of the colony by the Dutch in 1673, additional court districts were created around Upland and Whorekill. The latter was also known as Hoornkill, and is now the town of Lewes. 

The court at New Castle was left with the central portion of the colony. The jurisdiction left to the court at became New Castle County, and the county seat remained at New Castle until 1881 when it was moved to Wilmington.

In 1680, Whorekill District was divided into Deale County and St. Jones County. After this division, Lewes became the county seat of Deale, which was later renamed Sussex County. The former Upland District was named after the New Sweden settlement of Upland, and was renamed Chester County in 1682. Chester County is now located within the present boundaries of Pennsylvania.

Lord Baltimore, the Proprietor of Maryland, claimed all present-day Delaware, and organized its northern and eastern portions as Durham County, Maryland.

However, this county existed only on paper. The southern and western portions of present-day Sussex County were organized as portions of several adjacent Maryland counties and were not recognized as part of Delaware until the Mason-Dixon Survey was run in 1767.

In 1791, with the expansion of Sussex County to the south and west, the county seat was moved to Georgetown. The county seat of St. Jones (renamed Kent County in 1681) is at Dover.

The State of Delaware entered the union as the 1st state on December 7, 1787.

Delaware Counties Today

Today, Delaware is divided into 3 counties.  States bordering Delaware are PennsylvaniaNew Jersey and Maryland

The divisions, or “hundreds” as they are called, comes from the times when Delaware and Maryland were colonial holdings of Great Britain. While Delaware alone retains the use of “hundreds”, the origin of most “place names” in both states can be traced back to the times of British rule.

After 2000, a fourth “Appoquinimink County” was proposed to be carved out of New Castle County. The effort intended to end the zoning restrictions of the Unified Development Code on the undeveloped farmland. The proposed boundaries extended beyond the Appoquinimink Hundred to include all land south of the C&D Canal, with Middletown as the proposed seat.

Fun Facts about Delaware Counties

Counties by Year

County Size Facts

County Population Facts

Delaware City Facts

Delaware’s 10  largest cities (2018 est.) are:

  1. Wilmington (70,635) is in New Castle County
  2. Dover (38,079) is in Kent County
  3. Newark (33,673) is in New Castle County
  4. Middletown (22,582) is in New Castle County
  5. Smyrna (11,580) is in Kent County and New Castle County
  6. Milford (11,353) is in Kent County and Sussex County
  7. Seaford (7,861) is in Sussex County
  8. Georgetown (7,427) is in Sussex County
  9. Elsmere (5,981) is in New Castle County
  10. New Castle (5,529) is in New Castle County

Boundary Changes of Delaware Counties from 1673 to 1841

This Interactive Map of Delaware Counties show the historical boundaries, names, organization, and attachments of every county, extinct county and unsuccessful county proposal from 1673 to 1841.

List of Delaware Counties

List of Old Former / Extinct Delaware Counties

At least 10 Delaware counties that were established no longer exist. These are important for genealogy research purposes.

The below Delaware counties no longer exist:

Deale County, Delaware

Created on June 15, 1681 when Hoarkill County was renamed. Deale County was renamed to Sussex County on December 25, 1682.

New Amstel District/County, Delaware

Created on Sepember 12, 1673 as one of three countylike courts that became an original county. New Amstel County was renamed to New Castle County by November 11, 1674.

St. Jones County, Delaware

Created on 21 June 21, 1680 from New Castle and Hoarkill counties. St. Jones County was renamed to Kent County by December 21, 1682.

Upland District/County, Delaware

Created on Sepember 12, 1673 as one of three countylike courts that became an original county. Upland County was eliminated when the proprietary colony of Pennsylvania was established.

A southern remant of Upland County that had extended south of the Pennsylvania boundary around New Castle was added to New Castle County on August 24, 1682.

Whorekill/Hoarkill District/County, Delaware

Created on Sepember 12, 1673 as one of three countylike courts that became an original county. Hoarkill County was renamed to Deale County by 15 June 15, 1681.

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