Illinois Department of Transportation, Erica Borggren, Acting Secretary
Patrick J. Quinn, Governor
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Welcome to the Algonquin Bypass Website!

The Illinois Department of Transportation in cooperation with McHenry County initiated a Congestion Mitigation Feasibility Study to identify solutions to the congestion experienced at the Illinois Route 62 and Illinois Route 31 intersection in the downtown district of the Village of Algonquin. The proposed study and subsequent proposed improvement is located in southeastern McHenry County and encompassed review of traffic which passes through the communities of Algonquin, Lake in the Hills, Cary and Crystal Lake. The final outcome of the Feasibility Study was the implementation of a Western Bypass of the intersection.

This alternative provides the most capacity to handle traffic and had the least impacts on the communities involved. The proposed improvement will provide a transportation system improvement that will address capacity, operational and safety deficiencies, and satisfy 2030 travel demands along the Illinois Route 31 corridor between Edgewood Drive and Rakow Road. The final project will include the reconstruction and widening of portions of Illinois Route 31 along with the construction of a relocated Illinois Route 31 on a new alignment.

Project Start: September 4, 2012
Project End: Fall, 2014
Project Cost: $33,346,673.91
Project Municipality: Algonquin
Project County: McHenry

Project Flyer Project Flyer - Spanish

Project Flyer


Algonquin Western Bypass,  Contract 60F72

Algonquin Rd from Meyer Dr to IL Rte 31 (Main St):

  • Traffic is currently open to two lanes in each direction on Algonquin Rd.
  • Periodic closures of one lane will be required to finish the Entrance/Exit Ramp pavements and Curb, and to Finish the IL Rte 31 Bridge over Algonquin Rd and to Install Lighting and Traffic Signals.
  • Final Landscaping, Pavement Striping and Roadway Signing will proceed.

IL Rte 31 from Edgewood Dr to Huntington Dr/South Main St

  • Traffic is currently using the new Southbound lanes while Paving continues on the Northbound lanes.
  • Side Street aprons and Driveways will be finished after the remaining Mainline Paving is finished.
  • PCC Sidewalk Construction on the East Side of IL Rte 31 from Edgewood to Jayne St. will proceed.
  • Huntington Dr will re-open upon completion of the block retaining wall construction and installation of the new Street Lights and Traffic Signals.
  • Retaining Wall Staining will proceed.
  • Final Landscaping, Pavement Striping and Roadway Signing will proceed.

New Bypass Route of IL Rte 31 from Huntington Dr/S. Main St to Quarry Access/N. Main St

  • Construction of the Bridges over Crystal Creek and over Algonquin Rd will continue
    as well as finishing the various retaining wall pours.
  • The Noise Abatement Wall construction will proceed on the East side of IL Rte 31 from Railroad St to Crystal Creek.
  • Street Lighting and Traffic Signal work will proceed.
  • The remaining Pavements, Curbs and Shoulders will be placed.
  • Retaining Wall Staining will proceed.
  • The newly aligned MCCD Bike Path construction will proceed.
  • The new Towne Park parking lot work will begin.
  • Final Landscaping, Pavement Striping and Roadway Signing will proceed.

IL Rte 31 from Cary/Algonquin Rd to Linden Ave:

  • One lane in each direction is currently traveling on the new Southbound lanes of IL Rte 31.
  • The new Northbound lanes will be completed as well as all adjacent Driveways, Curbs and Side streets.
  • Traffic Signal and Lighting work will proceed.
  • Final Landscaping, Pavement Striping and Roadway Signing will proceed.

This site has been created to provide one location where the public can get details about the Western Algonquin Bypass project scope and the construction staging and schedule. The information is intended to help you understand what we will be doing and when the work is anticipated to take place.

As the Department works to make this section of roadway safer for the future, we want to make sure users, residents and local business owners have up to date information on the progress of the project. If you have any questions about the project that have not been answered with the information on this site please use the “Contact Us” section and a response will be sent to you.


Did you know work zone fatalities are down 29.6 percent compared to 2003? Aggressive law enforcement and awareness campaigns and significant improvements to work zone safety traffic control reduced Illinois work zone fatalities from 44 in 2003, including 5 workers, to provisionally 30 with 3 workers killed in 2010.
So, Give ‘em a brake…slow down for their sake and yours!
IDOT appreciates your patience and understanding as we work to improve the roadways in your community.


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