Cross Brook is a tributary of Six Mile Run in Somerset and Middlesex Counties, New Jersey in the United States.

The source of Cross Brook is near Suydam Road in eastern Franklin Park, at 40°27′7″N 74°33′33″W / 40.45194°N 74.55917°W / 40.45194; -74.55917. It flows through the Six Mile Run Reservoir Site and crosses Jacques Lane. After Jacques Lane it drains into the Six Mile Run at 40°28′23″N 74°33′6″W / 40.47306°N 74.55167°W / 40.47306; -74.55167.

Cross Brook is a slow-moving stream, although it is not marshy. Some species of fish may be expected to be found in it.

The Cross Brook starts as a lake which drains into grasslands, forming a marshy area around its source. It is still muddy farther downstream. It tends to be a wide, slow, deep stream.

Cross Brook is a short stream, only crossing one road. There are a few trails in the woods that lead to it.

• Nine Mile Run
• Steep Hill Brook
• Middlebush Brook

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  Cross Brook crossing Jacques Lane
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  Cross Brook flowing through grasslands near its source
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  Cross Brook crossing Jacques Lane

• List of rivers of New Jersey

• USGS Coordinates in Google Maps