State tax filing

I can't speak to the specifics of MD or NJ, but in general:

• You may need to file a non-resident tax return in any state where the partnership earned income.  The K-1 should break out what part of its K-1 may be subject to taxation in any given state.  Whether you need to file will depend on the rules and thresholds for each state (they all have different rules).
• The state where you are a resident will typically require that whatever you declare on your Fed return is the starting point for your state return.  But you may be able to claim credits for taxes you pay in other states, so that you're not doubly taxed on the same partnership income.