- Western Terminus:
- Whiteleysburg Road (MD 314) at the Maryland-Delaware state line
- Eastern Terminus:
- Bay Road (DE 12) in Frederica
- 16.19 miles
DE 12 is an east/west route that crosses the state. It begins at Whiteleysburg Road (MD 314) along the border with Maryland and runs northeast to Felton and then east to Frederica, where it ends at an interchange with Bay Road (DE 1). The entire length is a two-lane undivided road. The surroundings are rural enough that there is only one traffic light, located where it crosses South Dupont Highway (US 13) in Felton.