According to the State DEP, 175 streams in New Jersey support actively reproducing populations of wild trout.  Of these streams, 36 are regulated as "Wild Trout Streams" or "WTS".  This includes one that was added in 2007, a section of the Wanaque River below the Reservoir.  The WTS tend to support a larger fish population than the other 139 "Trout Production" streams which aren't so designated.  However, some of the streams (which were designated years ago) no longer support robust populations due to suburban sprawl, while some are still doing quite well.  You'll just need to check them out.

Source: Eastern Brook Trout Joint Venture, NJ State DEP Division of Fish & Wildlife, Google Earth

The above image was created in Google Earth.  It shows estimated brook trout habitat quality by subwatershed, overlaid with markers for each of the 36 WTS.  You can download from this website all of the information needed to recreate this image on your own Google Earth installation.  You can also click on an interactive map to zoom in on the markers in Google Maps.  Just click on the "NJ Interactive Map" link in the NJ Resources menu in the sidebar.

Note that wild trout regulations have also changed in NJ, and a 9" size minimum is now in effect across the entire state (not just on WTS).  A link to a summary of the special WTS regulations can be found on the NJ Resources menu in the sidebar.