Big Timber Creek enters the Delaware River between Brooklawn and Westville, just south of Gloucester City and across from Philadelphia.

In the second half of the 20th century, it suffered some ill effects of the rapid post–World War II development that impacted many of America's waterways.

It rises near Cross Keys in Gloucester County (under a housing development) at an elevation of about 160 feet (49 m) and flows northwesterly 2.4 miles (3.9 km),[1] fed by several streams from the east along the way, to its confluence with the Little Lebanon Branch just above Nash's Lake in Turnersville.

About 1 mile (1.6 km) north of its source, at the head of Jones Lake, Big Lebanon receives Long Hollow Branch.

Just beyond the dam, Chestnut Branch comes in, and Big Lebanon veers northwest to run along the south side of the Atlantic City Expressway.

It begins at Baum Pond (in 2007, dry) at an elevation of about 135 feet (41 m) near the intersection of Stagecoach Road and the Black Horse Pike.

Just below its head, the South Branch passes under the Atlantic City Expressway to be dammed about a third of a mile down to form Nash's Lake at an elevation of 79 feet (24 m).

From its origin, the North Branch skirts the northern edge of the world-renowned Pine Valley Golf Club and enters Lekau Lake a mile down.

[4] A teardrop-shaped impoundment about third of a mile (0.5 km) long, Lekau Lake lies at an elevation of 76 feet (23 m) in a hollow of the hills.

The North Branch then runs more to the west for a mile to Laurel Lake, a sinuous half-mile-long (0.8 km) impoundment which lies at an elevation of about 30 feet (9.1 m).

The North Branch continues its westerly course for three-quarters of a mile (1.2 km) below Laurel Lake, turning northward where Mason Run enters from the south.

This impoundment is a consequence of the constriction at the point about a third of a mile (0.5 km) down where the North Branch passes under the Black Horse Pike.

The main stream of Big Timber Creek begins in Glendora, just upstream from Clement's Bridge, at the confluence of the North and South branches.

A further half mile (0.8 km) sees Beaver Brook enter on the right, and the stream narrows again as it passes under Route 42 and the New Jersey Turnpike.

At least eight of the 14 or 15 sedimentary strata, or formations, laid down since the Cretaceous period appear at the surface in the Big Timber Creek basin.

Generally speaking, the surface of the area is weathered Cretaceous coastal plain consisting of quartz sand, with patches where gravel or clay are found.

Big Timber Creek dissects the inner coastal plain in the dendritic pattern characteristic of streams flowing over soft materials.

It has been cutting down through sand, clay, and gravel since the retreat of the last of the Pleistocene marine inundations which deposited fresh layers of sediment.