Primary elections will be held today in both the District of Columbia and Maryland. Polls will be open in both jurisdictions from 7 a.m. to 8 p.m.

In the District, candidates will be nominated for mayor, congressional delegate, D.C. City Council chairman, council member at-large and council members from wards 1, 3, 5 and 6. Only persons registered in the Democratic, Republican, D.C. Statehood, Socialist Workers or U.S. Labor parties will be allowed to vote in the District.

In Maryland, registered Democrats and Republicans throughout the state will choose party candidates for a range of posts, from govenor and attorney general to congressional and state legislative seats and county offices. Maryland voters not registered as Decorats or Republicans may vote only in the nonpartisan school board races.

In the District, write-in votes will be permitted. No write-ins will be allowed in the Maryland primaries.

In Washington, residents of precinct 123 who formerly voted at the old Congress Heights Elementary School, now vote at the new one at 6th Street and Alabama Ave. SE. Residents of precinct 24 who in the past have voted at the Morgan Elementary School will now vote at the Marie Reed Learning Center, 2200 Champlain St. NW.

District voters requiring additional information should call the D.C. Board of Elections and Ethics, 347-9725, or the League of Women Voters, 785-2616.

In Maryland, additional information can be obtained from county elections boards. In Montgomery, the number is 279-1507; in Prince George's 952-3270, and in Howard 997-7644.

Thirteen other states will hold primaries today.