Seneca is an unincorporated community in Union County, New Mexico, United States.

[1] Seneca is located on New Mexico State Road 406, 12.6 miles (20.3 km) north-northeast of Clayton.

Originally known as Cienaga, the name was corrupted by Anglophone settlers after the Civil War.

The first postmaster was Flora Blackwell.

This New Mexico state location article is a stub.