You can report the same line of work for two different companies, either your own companies or companies you worked for. However, if you performed the same type of work for several different companies, you should have only one Schedule C to report this combined income. This is true even if you worked in two different states.
But if you formed an LLC in two different states, you would report the activity for each one separately.
You will need to track the income for work performed in each state, since you will only be taxed for work performed in that state. Further, if you worked remotely, consider exactly where the work was performed and not the location of the company who hired you.
For instance, if you created a website for a company in New York and another in California while you lived in Illinois, you would have only an Illinois state income tax return. But if you lived in California while you created the website, you may have to file a California tax return.
TurboTax will help you determine what state tax returns you need to file, based on the information you enter during the main interview sections.
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