While you can incorporate in any U.S. state you wish, there is no legal requirement that says you have to incorporate in the state in which you live and work; the rule-of-thumb is to incorporate in the state that your company has its principal operations, especially if your business is primarily within one particular state. However, there may be good reasons not to incorporate in your home state (e.g., other states have more flexible corporation laws, more tax benefits, or no corporate income tax).
The general rule is to incorporate where you will do most of your business. This is particularly true for small businesses unlikely to conduct out-of-state transactions. If your business grows or you make changes that require you to work in another state, you can always register in that state. To understand the requirements for registering a new business, visit the assessment, business services or similar business agency in your state government.
If you decide to incorporate in another state, you will be considered a foreign corporation and will need to register in that state before starting to do business there. For example, if you own a trendy ladies’ shoe store in Maryland and want to open another in Pennsylvania, you will need a Foreign Filing Certificate or Certificate of Authority for Foreign Corporation from the Secretary of State in the area where you would like to do business. Most states require that out-of-state corporations pay a filing fee in order to register as a foreign corporation. Depending on state tax law, you will have to account for your foreign corporation in your state income taxes or be required to report in both states. To ensure that your new business complies with your state's legal requirements at every stage in the corporate formation process, you may wish to consult an experienced business or tax attorney.