If you established a new permanent home in another country, then you are no longer a Maryland resident and will not have to pay MD income tax.
Maryland says:
A taxpayer not only has to abandon the taxpayer’s old domicile, but the person must establish a new domicile. In order to establish a new superseding domicile, the taxpayer must be physically present in the state or foreign country that the individual intends to be the new domicile.
For example, a taxpayer cannot leave Maryland for an assignment in Spain, but claim Florida as their new domicile without being physically present in Florida and without taking steps to establish the new Florida domicile.
Administrative Release No. 37
You may be able to claim a foreign earned income exclusion if you are a resident of another country or are physically present in a foreign country or countries for at least 330 full days during any period of 12 consecutive months.
Foreign earned income exclusion
You can pay all your taxes due when you file your return, but you will probably pay penalty and interest. IRS expects you to pay estimated tax if you expect to owe at least $1,000 when you file your tax return.
Basics of estimated taxes for individuals
