If our website is abc.com I am wanting to create a subdomain or subdirectory for each major city for SEO targeting purposes. But I want each domain to go to our see the same content from the main website abc.com.

What's the best way to accomplish this? Duplicating our main page over and over sounds terrible , especially when trying to make changes down the road.

Should we create an alias for each location? example.. abc.com/new-york, abc.com-chicago, etc...?

If we go that route how does google acknowledge that? Would that mess up our SEO or help?

Thanks!