The US region
The United States Patent and Trademark Office is a federal institution so it grants your trademark protection in all US states.
At the same time, USPTO takes into consideration the «first to use» principle (it recognises an unregistered brand being used as a trademark). This is why many people chose to not register their brand as a trademark. However, is it is still highly recommended to register a trademark to establish ownership and to avoid any infringement problems and potential lawsuits. The same works for common law rights that correspond to the trademark protection which is based solely on using your trademark in commerce within a particular geographic area. This limits your rights, as you can only enforce your trademark rights for the specific area where your trademark is used.
Despite the fact that in order for this principle to work the brand should qualify all the criteria, one of its implications is that the trademark name should be chosen and verified carefully.
US trademark definition
According to US Patent and Trademark Office, almost anything can be a trademark if it indicates the source of your good and services. It could be a word, slogan, design, or combination of these. It could even be a sound, a scent, or a color. You can find trademark examples here.
Trademarks are typically creative or unique, setting you apart from your competitors. These trademarks include fanciful, arbitrary, or suggestive trademarks.
— Fanciful trademarks are invented words. They only have meaning in relation to their goods or services.
— Arbitrary trademarks are actual words that have no association with the underlying goods or services.
— Suggestive trademarks are words that suggest some quality of the goods or services, but don’t state that quality of the goods or services outright.
US Patent and Trademark Office fees
The lowest filing fee is $250 per class of goods/services.
Registration process duration and registration validity
The US trademark registration process takes from 12 to 18 months if no one objects during publication. A US trademark registration lasts for 10 years but can be renewed indefinitely.