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Chances are that this site is part of a  private network of sites being prepped for link building. They start by doing little wrong but building good PA/DA etc... and adding content in a specific genre Then suddenly links will start appearing on there in a short period of time and then eventually it will get caught by Google and possibly any sites linking from it will have their gains taken away or worse they may also get penalised in some way. There is NO secret sauce any more in link building. If they wont tell you then its grey/black hat and will get you penalised somewhere down the road. You can use link discovery tools to keep an eye on new links, like Majestic. But I would only go with transparency from an SEO company or your in for a a quick win and a terrible end.

As Patrick Mentioned there is no clear one thing to do, i would recommend running your site through screaming frog or looking into crawl errors with Moz and make sure your site is optimized.. ensure that all relevant tags are filled and optimized.. You'd be surprised how much of a difference it can make. Hope that helps & good luck.

It's a very real possibility that Google will tag these sites as duplicate content, and only rank the "original" content creator - whatever it deems that to be. It may be more productive to have one site, and a location-specific page for each site.  You can 301 redirect the unique URLs to each location-specific page if you still want to have unique domain names for each location.