If my cousin lives in my home in another state than I currently live and only pays enough to cover mortgage, is that considered a rental property?

[ThomasM125]

Yes, the payments you receive should be entered as rental income. You can deduct the mortgage interest, property taxes, insurance and other expenses of maintaining the house from the rental income.

[Hal_Al]

Maybe, but probably not.

If the amount he is paying is close to fair market rent, then you must treat it as a rental. 

Otherwise, he is only "sharing expenses"  and not paying rent.  You have a 2nd home, not a rental unit. 

[TomD8]

To expand on @Hal_Al 's answer, if you are not renting to make a profit, you report the income on Schedule 1, line 8 - not on Schedule E.

In TurboTax, go to Less Common Income > Miscellaneous Income > Other Reportable Income > Other Taxable Income.

If you itemize your deductions, you can include your mortgage interest and mortgage insurance premiums (if you use the property as your main home or second home), real estate taxes, and casualty losses from your not-for-profit rental activity when figuring the amount you can deduct on Schedule A.

https://www.irs.gov/publications/p527