It stretches along six miles of the Passaic River starting at Bloomfield Avenue in Fairfield, and ends just beyond South Orange Avenue in Livingston. The 1,360-acre park is primarily a wetlands preserve and remains undeveloped. The former Park Commission first began acquiring this land in 1955. Money to purchase the first piece of property came in part from the sale of Oraton Parkway to the New Jersey Highway Authority. Over subsequent years, other land was purchased from more than 70 individual landowners.
Additional acquisitions continue to occur even today.
Charm Acres, a picnicking and camping area, and the Center for Environmental Studies are located here. The building on Eagle Rock Avenue that was converted into the Environmental Center, located near the bridge over the Passaic River, was once a tavern and stagecoach stop. It was a welcome stopping point for those traveling toward Morristown. Hatfield Swamp is part of West Essex Park. The Lenape Trail is here, extending northeastward from Eagle Rock Road.