El Dorado County’s new Mosquito Road Bridge is scheduled to open to traffic Saturday, Sept. 26, providing a two-lane crossing over the South Fork of the American River for the Mosquito and Swansboro communities northeast of Placerville.

The county will hold an opening ceremony at 10 a.m. Friday, Sept. 25, but the bridge will remain closed to public traffic until the following day, according to an announcement from the county’s Department of Transportation.

The roughly 1,200-foot-long concrete bridge bypasses the winding descent to the old suspension bridge and the hairpin turns on both sides of the canyon. The new alignment shortens a 1.3-mile stretch of Mosquito Road to about 0.3 miles, according to county project documents.

Aerial footage captured Sept. 22, 2026, shows the new Mosquito Road Bridge.

Mosquito Road is one of two access routes serving Mosquito and Swansboro. The county’s environmental review described the old crossing as a single-lane timber suspension bridge just 9 feet wide. Large emergency vehicles could not use it and traveled along Rock Creek Road, a detour of as much as 20 miles. Improving access for emergency responders was among the benefits identified in the review.

The old bridge dates to 1867 and was rebuilt in 1939 using its original foundations. Keeping it in service has required repeated repairs and road closures. In its 2017 environmental documents, the county reported that maintenance could close the crossing for up to a month each summer.

Supervisors approved the replacement project’s environmental review in August 2017 and awarded Shimmick Construction a $74.4 million construction contract in May 2022. At the time of the award, the county estimated the full construction phase at $93 million, including construction management, testing, design support and contingencies. County records identified the federal Highway Bridge Program as the source of nearly all project funding.

The opening follows several revisions to the schedule. When supervisors awarded the contract, the county anticipated completion in spring 2025. A December 2025 town hall presentation later gave a June or July 2026 public-opening target, as Onsite Observer reported in February.

Building the crossing required temporary access roads and crane platforms on both sides of the river. Crews constructed the bridge in sections extending outward from its two main concrete piers, gradually connecting the structure across the canyon. The work also included retaining walls, drainage improvements and new roadway approaches tying the bridge into Mosquito Road.

County plans call for retaining the old bridge and converting it for bicycle and pedestrian use through a separate construction project. Vehicle access would be blocked once traffic shifts to the new crossing, according to the county’s construction contract report.

There will be no on-site public parking for Friday’s ceremony. A free El Dorado Transit shuttle is scheduled to leave the Placerville Library at 9:30 a.m. and return after the event. Attendees are asked to reserve a seat by Tuesday, Sept. 22, by emailing MosquitoBridgeRSVP@edcgov.us.