Md. Code, Elec. Law § 2-302

(a) (1) The State Board shall be open for business during regular business hours on each State government workday. (2) The State Board shall remain open until 9 p.m. on the last day for the filing of a certificate of candidacy for each election conducted under this article. (b) (1) Each local board shall be open for business: (i) on each day that is a county government workday in its county; (ii) on each election day; and (iii) until 9 p.m. on the last day for the filing of a certificate of candidacy for an election conducted in the county, if a certificate can be filed with the local board. (2) The members of each local board shall be available as needed on an election day and during the canvass of each election. (3) The hours that a local board is open for business: (i) may be the same as the regular business hours of its county government; or (ii) for the convenience of the public, may be different from the regular business hours of its county government, except that the number of business hours the office is open each business day must be at least equivalent to the number of business hours that the county government is open.