Maryland Tax Residency (183-day rule)

Key parameters
Threshold	183 days
Period / Window	Tax year (1 Jan – 31 Dec)
Counting	Any part of a day
Alternative	Domicile
Additional requirements	Abode for more than 6 months

This applies to anyone keeping a place to stay in Maryland while treating another state as their own. You are a Maryland resident if either of these applies:

• Domicile on the last day of the tax year — Maryland is your permanent home at 31 December.
• Abode plus days — you maintain a place of abode in Maryland for more than 6 months of the tax year and are physically present in the state for 183 days or more.

Domicile is tested at a single point rather than across the year, so the timing of a move around 31 December decides how the whole year is treated.

• 183 qualifies, not 184. Maryland's threshold is 183 days or more, so a count that would fall short in Virginia or Pennsylvania is enough here.
• Six months is enough for the abode. Unlike states demanding the home for substantially all of the year, Maryland asks only for more than six months.
• Domicile turns on a single date. Being domiciled in the state on 31 December decides that route, which makes a December move unusually consequential.
• A 24-hour period cannot be two days. The counting rule stops a single continuous stay of a day or less being counted twice because it straddled midnight.
• The DC and Virginia borders make this easy to trip. Short, frequent crossings each add a full day, and the region's commuting patterns produce high counts quickly.

A resident is taxed on income from all sources while a nonresident pays only on Maryland-source income, so an error usually surfaces as out-of-state earnings never reported while another state taxed the same income. The Comptroller charges interest from the original due date and adds penalties for filing late and for underpaying, with greater exposure where an understatement is treated as deliberate. Professional tax advice is strongly recommended in situations like this.

An apartment and a regular commute

You are domiciled in Delaware, rent a Baltimore apartment from January to October, and are in Maryland on about 200 days. The abode ran past six months and the count passed 183, so you are a Maryland resident.

A count that lands exactly on the line

You keep a Maryland home all year and are present on exactly 183 days. Because the rule is 183 days or more, that is enough, where the same count would fall short in a state using "more than 183."

A move completed in January

You leave Maryland for North Carolina but only complete the move in early January, having spent under six months in Maryland accommodation. Domicile on 31 December was still Maryland, so that year remains a resident year.

• Comptroller of Maryland — Administrative Release 37, residency
• Code of Maryland Regulations — 03.04.02.01, definitions