Delmar is a town in Sussex County, Delaware, United States, on the Maryland border along the Transpeninsular Line.

The name is a portmanteau of the states whose border this railroad center straddles - Delaware and Maryland.

These new developments immediately made the Delmarva Peninsula an important link between the north and south.

As a result of these developments, a tremendous influx of experienced railroad men moved into the community and considerable extra employment was furnished for local townspeople.

New dwelling units sprang up all over town and new businesses were established to meet the demands of its growing population.

An examination of this charter and the laws of Maryland fails to reveal any mention of the twin town of Delmar, Delaware.

The construction of the sewerage system in 1927 was considered the first joint project between the two towns in that the law provided that both towns would maintain the outfall sewer with Maryland paying the expenses and billing the Delaware side one-half of all costs.

The biggest push towards abolishing the jurisdictional, legal effects of the state line came when the Lions Club voted to sponsor a project for the consolidation of the two school systems in the town.

[4] According to the United States Census Bureau, the town has a total area of 0.9 square miles (2.3 km2), all land.

DART First State operates the Route 212 bus that connects Delmar to Georgetown via Laurel, Seaford, and Bridgeville.