The Wetland Pond at the proposed Expo Idaho Park

Idaho Expo Riverfront Park

Envisioning A New Riverfront Park

RIOS participated in the park design competition to design the future of the 90-acre site at Expo Idaho, the former site of the Les Bois Park horse racing track. Dubbed Expo Reach, we imagine a dynamic, climate-adapted park where visitors can connect with nature, relax, and play. By creating shared experiences and integrating ecological principles, our vision transforms the Garden City grounds into a year-round riverfront center for the community.

A new green jewel along the river

Our vision for the new park in Boise, Idaho, is guided by the following design principles:

Foster Community
Engage the River and Promote Resiliency
Connect to Nature
Provide Shade and Areas of Respite
Promote Safe Walkability
Promote Recreation and Play for All

Expo Idaho Park Proposed Site Plan

Expanding the River's Edge

The park is positioned to maximize the experience along the Boise River, extending the river footprint into the historic floodplain and including several local ecologies. This design brings the river experience into the site to connect the community more deeply to this vital recreational corridor. A sports meadow, play gardens, and walkways create shared experiences for everyone as connections to the water overlap with community-oriented programs.

Diagram showing how the design would transform relics and bring the community to the river

Adventure Island

Sports Meadow

Experiential circuit linking the entire park

Reinventing the Grandstand

With our proposal, the existing horse track and grandstand will transform into an experiential circuit linking the entire park. It incorporates biking and walking paths, as well as boardwalks, sports fields, play gardens, adventure areas, wetlands, and the river. Fishing pier and overlooks enhance connections to the river, providing visitors access to curated moments and proximity to the water.

An iconic feature of the site, the grandstand provides a large gathering area. Our proposal envisions the grandstand as a super pavilion for year-round events, food and beverage activations, and community experiences. The new grandstand will serve as the park’s anchor and gateway for arrivals.

Open up Grandstand at grade to improve flow and visibility at Plaza

Activate the Grandstand plaza experience with events

Connect the plaza and grandstand experience

Engage and extend entry sequence with a shade canopy

Expo Gateway

As a climate-adapted park, Expo Park's landscape design addresses future challenges.

Seasonality

This park’s design provides a year-round gathering space for Ada County residents. Meadows, topography, and ecological features support seasonal events, biodiversity, and unique play opportunities. Visitors can also access the site from all sides because the design considers the fluctuation of high and low tides.