Project Description

The Big Walnut Interchange is a planned freeway interchange on I-71 at mile marker 124, at or near Big Walnut Road in Orange Township, Delaware County, Ohio near Alum Creek State Park.

Current Status of Project

The Delaware County Engineer’s Office (DCEO), working in partnership with the Ohio Department of Transportation (ODOT), is currently working on a feasibility study to determine the transportation needs in Orange and Genoa Townships in the vicinity of Big Walnut Road and I-71.

In January 2018, the ODOT Transportation Review Advisory Council (TRAC) approved Tier II status for the project, which means that the project is authorized for continued development through preliminary engineering and detailed design.  The next step after approval of the feasibility study will be submitting an Interchange Justification Study (IJS) to ODOT and the Federal Highway Administration (FHWA) for review.

Currently, DCEO has no established schedule for construction of the interchange, though we know that with the amount of work remaining, construction could not start sooner than 2023.  Once the feasibility study is approved, Delaware County will be working with ODOT to share more information about the project, including cost, design alternatives and schedule.

Frequently Asked Questions

Q:  Why is this project needed?

A:  The project is proposed to improve access to the interstate highway network and other principal highways in the area for the developed areas of suburban Southern Delaware County.  The I-71 and Polaris/Gemini interchange (exit 121) does not provide reliable, safe or efficient means of accessing the regional transportation network for a large portion Delaware County and the majority of its population.


Q:  Is this the same thing as the planned Sunbury Interchange at US 36/SR 37?

A:  No, the Big Walnut Interchange is a separate project with a conceptually different purpose – that is, to serve the transportation needs of current residents and businesses in Orange and Genoa Townships in south-central Delaware County, and the population growth that has already occurred in this area over the last 20 years.

By comparison, the interchange modification at US 36/SR 37 near Sunbury is being developed to address congestion at the existing interchange that is expected to occur over the next 20+ years as new commercial and residential development occurs in the vicinity of that interchange.  For more information about the US 36/SR 37 interchange project, visit ODOT’s project webpage.


Q: How long has this project been planned?

A:  An interchange in this vicinity was considered as early as 1987 in the Southern Delaware County Thoroughfare Plan, which contemplated an interchange north of the current location of the Polaris/Gemini interchange to serve Alum Creek State Park.  The Polaris/Gemini interchange was eventually built south of the location shown in the throughfare plan.

In the late 1990’s, recognizing the massive amount of development that was being planned and built around Polaris, a second interchange for southern Delaware County was proposed farther north of Polaris, in the vicinity of Big Walnut Road.  This was formalized with approval of the 2001 Delaware County Thoroughfare Plan, which shows the interchange at Big Walnut Road.


Q: Wasn’t this interchange was studied a few years ago? Why isn’t it already built?

A: A study was done in 2008-09 looking at the feasibility of building an interchange at Big Walnut Road.  That study concluded that the interchange would, indeed, serve a lot of traffic; however, the extra traffic using the interchange destined to/from Columbus would require an additional lane to be built on I-71 between Big Walnut Road and Gemini Place and/or I-270 so as not to degrade the traffic operation on I-71, which is an interstate freeway carrying over 80,000 vehicles each day between Ohio and Kentucky.  The estimated cost of this freeway expansion was well beyond any financial means of Delaware County or ODOT at the time, and development of this project was suspended while other projects in the area, including the Gemini/Ikea Way extension, widening of Worthington Road, South Old State Road, Powell Road, Lazelle Road, Cleveland Avenue at I-270, US 23 at I-270 and other roads in the area to enhance already existing means of accessing the interstate highways in the area.


Q: Why are you looking at this interchange again?

A: As the other local road network improvements mentioned above have been completed or will be completed in the next few years, and congestion at existing interchanges remains a problem, there are few, if any, other remaining options to improving access to the freeway network besides adding more interchanges.  Projected population growth in Orange and Genoa Townships, as well as continued commercial development in and around the Polaris area, is expected to consume much of the traffic capacity that has been created by other road improvements in the areas, so there will ultimately need to be more points of access to the freeway network for residents of Southern Delaware County.


Q: Besides improving access for residents, why is the interchange needed?

A: Alum Creek State Park is one of Ohio’s top outdoor recreational destinations and a premier location for camping and boating.  The park generates tourism spending in the area and in Ohio which boosts business spending and employment and encourages physical activity to improve health and wellness.  Access to the park, especially for recreational vehicles and vehicles with boats in-tow, is currently not as good as it could be.  The circuitous and congested routes that visitors must take to get to Alum Creek State Park from I-71 using the Polaris-Gemini exit, or from the US 36 interchange in Sunbury, can be improved with an exit that is closer and easier to navigate to reach the major park amenities including the boat launches, campground and below-the-dam park.


Q: Is the Big Walnut Interchange being proposed to serve new commercial development in the area?

A: No. The interchange is being proposed to address needs of existing development within Orange and Genoa Townships as well as Alum Creek State Park.  The area surrounding the proposed interchange is mostly built-out with residential development, or is preserved in perpetuity for public park use within Alum Creek State Park.  There are only a few undeveloped tracts of land remaining in the vicinity of the interchange.  Land use is determined by local zoning regulations and the Orange and Genoa Township Comprehensive plans contemplate mostly rural residential and planned residential development in the remaining undeveloped areas.


Q:  Does this project have anything to do with the proposed “Planet Oasis”?

A:  No. The proposed Big Walnut Interchange predates the proposed Planet Oasis by about 20 years.  The primary need for the Big Walnut Interchange is to serve existing southern Delaware County residents and businesses by improving access to the freeway network.


Q: Where would the ramps to and from I-71 go, and what would the limits of work on the local road network be?

A: The study is looking at three different conceptual locations for ramps to/from I-71.  Ramp terminals (intersections on the local roads) could be located on Africa Road north of Big Walnut Road, Africa Road south of Big Walnut Road, or on Big Walnut Road.  Until more detailed engineering and environmental investigations are done, we don’t yet know where the best location of the on/off ramps would be.

The limits of work on the local road network are not known at this time; but the study area of the project extends along Lewis Center Road west to South Old State Road, and on Big Walnut Road east to State Route 3.  The north limit of the study area is Lewis Center Road (East), and the southern limit of the study area is Africa Road at I-71.


Q: How will this project be paid for?

A: The feasibility study is being paid for with federal highway Surface Transportation Program funding.  It is anticipated that the acquisition of property and construction of the project would be paid for with a combination of local, state and federal transportation funding.


Road Closure Information


Project Schedule

Feasibility Study: 2016-17

Preliminary Engineering (if project advances): 2018-20

Property acquisition: 2020-21

Construction: 2022+


Engineering Information

Preliminary engineering by AECOM of Columbus, Ohio.


Construction Information


Estimated Project Cost

The preliminary cost estimate for the project is $68 million which includes the local road improvements in the vicinity of the interchange on Africa, Big Walnut and Lewis Center Roads as well as adding a fourth lane to I-71 from Gemini Place to the proposed interchange at Big Walnut Road.


Questions or Comments?

Your comments or suggestions are important and we would like to hear from you about the project. Please contact Robert Riley, Chief Deputy Engineer at 740-833-2400 or send your questions or comments to