I'm looking for a database of US Maine companies.
All I found is the page where you can search for companies from here. But I cannot find anywhere a place to download a list.
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https://opencorporates.com/registers is a nice starting point to check whether data is freely available to download.
For example if we check https://opencorporates.com/registers/147 which is Maine they are giving it a score of 0, which means the data is not free available for download.
This doesn't mean you cannot find this database anywhere, but you'll most probably need to contact US Maine jurisdiction or look for paid database somewhere. For example I can see sites like https://mainecorporations.info/ have the database imported in their website. OpenCorporates also does have the entries imported. Which means it's not impossible to find but just hard.
There is also the possibility that these sites are using some kind of automatic scraper bot, which crawls the official website and collects the data.