The Depot Building is located on the west end of the Trailhead Park, and was envisioned to be reminiscent of what was once along the railroad tracks years ago.

The Depot Building is an air-conditioned, approximately 100-person capacity room that houses many old photographs and relics from Mandeville's past.

The design of the building is a composite of depot buildings that were once seen throughout the area. A static display of photographs originally compiled by the St. Tammany Historical Society for City Hall, are now housed in the building.

The displays in the Depot Building try to give visitors a glimpse of Mandeville's unique history.

Incorporated as a town in 1840, Mandeville was originally used as a retreat for the wealthy families of New Orleans, who came to escape the heat of the city and threat of disease, mainly Malaria. Before the bridge was built, people came over Lake Pontchartrain with the steamer ferry service. Once the first span of the 24 miles Causeway Bridge was built in 1956, and a second span in 1969, growth rapidly became the rule. Many families moved the to area while maintaining their business and work back in New Orleans. Mandeville then became accessible to the less wealthy people and subdivisions began to pop up over the area.

On June 18, 1985, then governor, Edwin W. Edwards, proclaimed the "City of Mandeville" from the town of Mandeville. The population of the Mandeville had grown to over 5,000 persons.

The Tammany Trace runs along the north side of the Trailhead Park and was Louisiana's first and only rails-to-trails conversion. The Trace is a scenic 31-mile asphalted recreational corridor for pedestrians, bicyclists, equestrians, rollerbladers, and joggers. The trail makes its way through five communities along the Northshore of Lake Pontchartrain in St. Tammany Parish: Covington, Abita Springs, Mandeville, Lacombe, and Slidell.