At least six Seafords exist in the world: Seaford, on the south coast of England; Seaford, Delaware, and Seaford, Virginia; Seaford, Long Island, New York; Seaford, Victoria, Australia, and Seaford, South Australia, Australia.
When using a search engine, please be aware of the six locations.
Apparently, Washington Avenue is the sole street in Seaford named after an owner of slaves. Jackson Avenue is certainly not named after President Jackson.