This can be very subjective. Consider how nonprofits and other grant-makers define your community. In Cincinnati, Ohio, Greater Cincinnati is defined as 10 counties spanning three states. In Palm Beach, Florida, it is one-half of one county.
Be sure to include each county that your nonprofits typically serve. This is critically important. If nonprofits in your area typically serve five counties, for example, but you believe the three-county area is the ideal geographic boundary, you are setting up your process for failure. Here’s why: when your Impact100 chapter begins to award grants, the grant agreement will specify that all grant dollars stay in your local (defined) community. If your defined community is smaller than the typical service area for your nonprofit applicants, you will, at best, be creating an administrative burden on your grant recipients and, at worst, disqualifying nonprofits from applying for your grants at all.
However, you define community, be certain you can reach out to nonprofits, corporate supporters, and potential members from one end of your service area to the other.