AVAILABLE NOW: Front-End Developer Handbook 2017
The national average in the U.S for a front-end developer is $75k.
An experienced front-end developer potentially can live wherever they want (i.e., work remotely) and make over $150k a year (visit angel.co, sign-up, review front-end jobs over $150k).
Image source: http://intersog.com/blog/chicago-tech-salary-guide-2015/