The first incarnation of what would become the Northport-East Northport Public Library was located  in the First Presbyterian Church on the corner of Main and Church streets beginning in 1880.

From then until 1914, the library found several homes. But in 1914, it moved in to a new permanent building at 215 Main Street, currently the home of the Northport Historical Society, built with funds from philanthropist Andrew Carnegie's foundation.

By 1965, however,  the library had outgrown that building, as well, as the population served by the library district had grown from nine thousand five hundred in 1950 to twenty-eight thousand in 1960.

The community voted in 1963 to purchase land at the corner of Laurel and Scudder Avenues. Soon after, it voted to build a 20,000 square foot library on this site. Construction was completed in 1966.

By 1986, the library had once again outgrown its space. After exploring a range of options, the library board proposed a plan in 1995 to renovate and expand the library building from 20,000 to 36,000 square feet. The community overwhelmingly approved a $7.4 million bond issue to fund the project in September of that year.

In November 1996, ground was broken for the Northport building expansion. The building closed in October 1997 as construction proceeded.  In August 1998 the expansion project concluded with the opening of the new expanded library.

To celebrate its 90th anniversary in 2004, the Northport-East Northport Public Library embarked on a project to expand its services by creating a welcoming outdoor terrace. With support from the community the Library Courtyard was completed in 2005.

The library has a café. It has a teen room and a children's room. It also has an extensive movie and music collection.