A closed-captioning company working out of the United States can service clientele all around the nation and even around the globe with the advances in modern-day technology.
A company based out of southern California not only reaches the heart of Los Angeles' TV and film industry, but can also service markets like New York, Chicago, Dallas, Atlanta, Boston, Memphis, Milwaukee, and Austin, for example. The closed-captioning market for a southern California-based company is not only limited to the United States, clients abroad (Europe, Australia, et cetera) that are broadcasting in the United States can find it beneficial to use a closed-captioning company based in the U.S.
You may wonder how that can be possible, but it is because the present and the future trend is to use a tapeless closed-captioning method. You can upload digital video files (often referred to as proxy files) directly to your captioning company's FTP site where they can either send you back a captioning file or send the file directly to the stations' play-servers.
Don't limit your closed-captioning service to your hometown or home state; think nationally and internationally. You may just get a better closed-captioning service elsewhere.