An abandoned inn (called Munn Tavern) was purchased and became the new home for the library in 1898.

A branch was established in 1899 in a rented room in the real estate office of John Mancini on Bellevue Avenue, near the Upper Montclair train station.

In 1913, the Carnegie Corporation gave Montclair a second sum of $40,000 for the construction of the Bellevue Avenue Branch.

It drew the attention of Director Hans Burger, who developed a film of the same name in 1940, which was distributed by the Museum of Modern Art and shown throughout the world under the auspices of the U.S. Department of State.

In February 1942, International Business Machines Corporation (IBM) designed the first ever punch card data processing system for the library, also making the first public library in the United States to have a computerized circulation system.