Health tech is relatively scattered with hubs all across the US. I suspect that you may be looking for healthcare startups. There's a large concentration in San Francisco, NYC and Boston. The DC area has the government agencies, which may be of interest to you.

My suggestion is to look through the techcrunch healthcare section for companies that look interesting: https://techcrunch.com/tag/healthcare/ and look through each month's HN Who's Hiring for healthcare

Additionally to add some nuance to angersock's comment: healthcare has a lot of compliance requirements and there are few incentives to adopt new tech. This can be a pain as you have real limitations on what you can do compared to other industries. That said, healthcare startups are doing some really cool things and there are bright spots among insurers and hospital systems.