St. Charles County is preparing to upgrade Highway N, a roadway that will serve new housing developments in the area. The project is designed to improve access and manage the increased traffic expected from the region’s growth. County Executive Steve Ehlmann noted that the area’s flat terrain and location outside a floodplain make it suitable for development and that improved roads will support residents’ travel to work and school.
According to St. Charles County, the Highway N project is scheduled to begin in 2027, following nearly a decade of planning by county transportation officials. Amanda Brauer, St. Charles County’s Managing Director of Transportation Planning, said the county has been acquiring right-of-way and completing environmental and design work. The project will be carried out in two phases, starting with a major expansion of the highway.
The first phase of the project will widen Highway N to three lanes in each direction between Hawk Ridge Trail and Sommers Road, then reduce to two lanes per side up to Ebert Lane. This four-mile stretch represents the main capacity improvements of the project. Funding for this segment, estimated at $80–100 million, will come from local, state, and federal sources, with more than $46 million already allocated from local Transportation Sales Tax revenues.
The second phase will extend the four-lane section from Ebert Lane to areas west of Forrester Drive and eventually create a new connector from Highway N to Buckner Road and Highway Z. Scheduled to begin after the completion of a roundabout in 2029, this roughly one-mile extension is smaller in scale and expected to have less impact on budgets and timelines. The project is designed to accommodate traffic from more than 1,700 planned residences. Robert Myers, Director of the County Planning and Zoning Division, projected that these homes could be built over the next five to ten years, supporting the area’s anticipated growth.
These improvements will ultimately link Highway N to David Hoekel Parkway in Wentzville, creating a circumferential route designed to improve traffic flow and connectivity. The upgrades aim to align roadway capacity with the area’s growth, supporting both new development and smoother commutes.
