Big Flat Brook (above Steam Mill Bridge) is a stocked trout stream in Sussex County, New Jersey, around Montague Township. 7.4 of its 7.4 miles (100%) run through mapped public land. New Jersey allocated 1,360 trout to it for spring 2026.
Bold where the stream crosses public land; faint and dashed across private land. Gauges are measurement stations; a nearby gauge may be on a different stream.
Stream types · New Jersey
Bold where the stream crosses public land
All 6 mapped parking areas and access points along the stream are on public land, from High Point State Park to Stokes State Forest. Distances are to the nearest bank.
1,360 trout stocked spring 2026. In-season stocking dates are on the state's schedule. Source: NJDEP Fish & Wildlife, 2026 Spring Trout Allocations, checked Oct 12, 2026.
Catch and release area: Rt. 206 bridge downstream to the Roy Bridge on Mountain Rd. (4.2 miles), including the Blewett Tract. Digest p. 20
Other sections of this water have their own pages: Big Flat Brook (below Steam Mill Bridge).
Rules: 2026 New Jersey Freshwater Fishing Digest, pages 16-21.
This section has no gauge of its own. The river's gauge is Flat Brook near Flatbrookville, NJ, on another section about 15 miles away; its flow is a good guide to this water, though levels here can differ.
Other streams in Sussex County: Musconetcong River · Paulins Kill · Pequest River · Wallkill River · Little Flat Brook · Clove Brook · Lubbers Run · Franklin Pond Creek
Check before you fish. Access, stocking and rules come from New Jersey's own data and can be out of date. Posted signs and landowners' wishes come first, and private land needs permission. You need a valid fishing license.