Sadly there are currently no cell phones being produced in the USA. For a short time the first model of the Moto X was American made. The company making the Moto X was sold and the production was moved overseas immediately with about 400 jobs.
There are news reports of course in 2017 that Foxconn will be building a factory in the USA to create either Apple phones or at least components. If you are aware of any cell phone company we may have missed please let us know.