Ellarslie, an Italianate villa, was built for Henry McCall Sr. of Philadelphia as a summer residence in 1848. The architect selected to design Ellarslie was John Notman, known for designing the first Italianate building in America in Burlington, NJ, and the first Renaissance Revival building, the Athenaeum in Philadelphia. Notman was locally recognized for also designing the 1845 expansion of the New Jersey State House and the design for the State Hospital, which was also begun in 1848.

In February 1881, Henry McCall Jr. sold Ellarslie to George Farlee for $25,000. Seven years later, in September of 1888, the city of Trenton acquired the property from Farlee for $50,000, which also included the surrounding 80 acres, which would become the city's first public park, Cadwaladar Park, designed by the father of landscape architecture, Frederick Law Olmsted.

The City of Trenton opened the first museum here in 1889, closing several years later. Ellarslie has been a restaurant, ice cream parlor and monkey house. The building itself has been home to several noted Trenton families over the years, and in 1971 renovations began to create the Trenton City Museum.

The Trenton City Museum opened in 1978 in Ellarslie Mansion with an exhibition from our permanent collection of Trenton cultural history. Ellarslie Mansion is included in the National Registry of Historic Places.

Ellarslie Mansion has been home to the Trenton City Museum since 1978.