Md. Code, Labor and Employment § 9-203

(a) Except as otherwise expressly provided, an individual is a covered employee while working for the employer of the individual:

(1) in this State;

(2) outside of this State on a casual, incidental, or occasional basis if the employer regularly employs the individual within this State; or

(3) wholly outside the United States under a contract of employment made in this State for the work to be done wholly outside of the United States.

(b) (1) An individual is not a covered employee while working in this State for an employer only intermittently or temporarily if:

(i) the individual and employer make a contract of hire in another state;

(ii) neither the individual nor the employer is a resident of this State;

(iii) the employer has provided workers’ compensation insurance coverage under a workers’ compensation or similar law of another state to cover the individual while working in this State;

(iv) the other state recognizes the extraterritorial provisions of this title; and

(v) the other state similarly exempts covered employees and their employers from its law.

(2) If an individual is exempted from coverage under this subsection and injured in this State while working for the employer of the individual, the sole remedy of the individual is the workers’ compensation or similar law of the state on which the exemption is based.

(3) A certificate from an authorized officer of the workers’ compensation commission or similar unit of another state certifying that the employer is insured in that state and has provided extraterritorial insurance coverage for the employees of the employer while working within this State is prima facie evidence that the employer carries that compensation insurance.

(c) Except as otherwise expressly provided, an individual who is employed wholly outside of this State is not a covered employee.