Throughout a public engagement project there needs to be a constant push to reach your audience. One way to do this is by reaching out to your champions and stakeholders. Stakeholders share a common audience with you and may be able to help you reach out to more people and regions.
Are your stakeholders actively participating in and/or promoting your engagement? If not, you may need to change your approach or use new tools. Consider sending them a letter or an email reminding them about your engagement.