Chapter designations correspond to Maryland counties, with the exception of one in Prince George's County: Patuxent. Choose a chapter close to your residence, your place of work, or where you like to bird, or select At-Large for information on joining MOS without belonging to an individual chapter. Membership in an MOS Chapter includes membership in the State organization and all MOS and chapter publications.

Details about chapter membership and activities can be found by clicking on the chapter of interest in the table below. A handy membership application form is also available.