Bay Shore is a hamlet and census-designated place (CDP) in the Town of Islip, New York, United States.

The land that would become Bay Shore proper was purchased from the Secatogue Native Americans in 1708 by local school teacher John Mowbray for "several eel spears".

The rural hamlet became popular with affluent New Yorkers looking to escape the city to white sand beaches of the Great South Bay and the fishing villages of Fire Island.

It was a tourist spot on weekends and during the summer, in large part because the newly built Long Island Rail Road enabled easy access from New York City.

[8] The population of Bay Shore increased significantly after World War II: from the mid-1950s through mid-1960s, a variety of housing developments were constructed on farms and unused woodlands.

Those developments were settled largely by working and middle class first-time home buyers from New York City.

[citation needed] Despite strains on the community brought on by sudden, substantial growth, the hamlet remained sound.

Without a local government, residents were unable to make decisions that were instead left to the Town of Islip and Suffolk County.

The population density and demographics shifted when rezoning permitted businesses, rental properties and multi-family dwellings where previously only single-family houses had been allowed.

Deinstitutionalization caused psychiatric patients of the nearby Pilgrim State Hospital to be hastily relocated to rental housing downtown, often without sufficient professional support.

The redevelopment of Main Street is ongoing; efforts include new sidewalks, antique-style streetlights, new landscaping and restored parks.

The Bay Shore Beautification Society transformed an empty lot on Main Street into a meditation garden in 2007, that has since been recognized for its excellent design.

Over the summer of 2010, a new water park was built at Benjamin Beach, which sits adjacent to the marina, with a renovated bath house and new landscaping.

Most of the old mall and adjacent buildings were replaced by new commercial and retail spaces, including a Lowe's home improvement center, a Target and a BMW dealership.

[15] The shape of Bay Shore CDP differed in the 2010 and previous censuses,[16] and so that boundary did not extend into West Islip School District.

[20] Bay Shore station is a stop on the Montauk Branch of the Long Island Rail Road.

The department is headquartered on Fifth Avenue, and two additional stations are located on Union Boulevard and East William Street.

[22] The ambulance service covers 25 square miles and is staffed 24/7 by volunteers ranging in certifications from EMT to Paramedic.