At least in the US, it is common to find open data repositories for large populations at the city, county, and state levels. These repositories pull together data from multiple sources for their area of interest. Some examples of these repositories are below. Note that sometimes open data repositories include GIS-formatted datasets and other times GIS data have their own separate repositories.
How to proceed:
Open data portals get their data from government agencies and organizations within their geographic area. Sometimes those portals are comprehensive and other times they only scratch the surface of what is available. Often the originating agencies offer more data than what they share with the larger portals. It's a good idea to identify the agencies that collect the kind of data you're interested in and look for the data they share. Some examples are below to give you an idea.
Questions? Contact reference@carleton.edu
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