Project Description

Somerset County is conducting a Concept Development Study for the Griggstown Causeway (CR 632) and its surrounding area.  The Causeway connects River Road (CR 533) in Montgomery Township to Canal Road in Franklin Township and crosses the Millstone River, D&R Canal Park and the Delaware and Raritan (D&R) Canal.  The Study Area includes the roadway network around the Causeway, including the following intersections:

1. River Road (CR 533) and Griggstown Causeway (CR 632)
2. Canal Road and Griggstown Causeway (CR 632)
3. Canal Road (CR 632) and Bunker Hill Road (CR 632)

Also included in the Study Area is Somerset County Bridge No. F0302, a one-lane truss structure that crosses the Millstone River.   A Study Location map can be found here:  Study Location Map

The purpose of the study is to evaluate current traffic conditions to determine if changes need to be made to improve safety and mobility by addressing general safety concerns, vehicular crashes, traffic congestion and sight lines.

Work efforts for this study will include performing data collection and data analysis as well as developing an alternatives analysis, soliciting public input and preparing a Concept Development (CD) Report.

Public Meeting

An in-person public information meeting was held the evening of Tuesday, July 1, 2025, at the County Administration Building in Somerville, NJ. The meeting's purpose was to inform local residents, officials, businesses and the general public of the status of the Griggstown Causeway (CR 632) Concept Development Study and present the project's Preliminary Preferred Alternative (PPA). Members of the public were able to speak with the County's engineers and consultant representatives, ask questions, and provide comments.

The County is seeking comments regarding the project and the proposed improvements.  Please provide comments using the online submission form below by Tuesday, July 15, 2025.

Meeting Notice

Meeting Presentation

Griggstown Causeway Road Closures

To sign up for Somerset County Safety Alerts, including county road closures, go to: https://www.co.somerset.nj.us/about/emergency-alerts. 

Below is a link to the National Weather Service (NWS) Gauge located at the Millstone River at Griggstown.  The Griggstown Causeway is typically closed to traffic when the gauge reaches approximately 9 feet.  Use of the NWS link is provided as guidance only.  Timing of  a road closure and reopening varies.

https://water.weather.gov/ahps2/hydrograph.php?gage=gtnn4&wfo=phi

Contact Us

Somerset County welcomes your feedback about this study.  For comments or questions regarding the study, please fill in the form below.