This institution can be a government agency (IRS, Medicare, the Food and Drug Administration, etc), a corporation (IBM, USAA, etc), a school district, a city department, a national restaurant chain, a hospital system, or other company/agency.
Note: This page is absolutely not an exhaustive set of resources or strategies. It's just a few starting points. Where and how you look will depend on your topic and organization!
Once you've identified the site(s) for your institution, you can use the domain search trick on Google to zero in on relevant information about them. Just add to your search terms site: and whatever the domain is. Try out the example below to see it in action!