On September 12, the city council of College Park, Maryland, voted 4-3 to allow all adult residents (except ex-felons) to vote in city elections, regardless of citizenship status. See this story. College Park is in Montgomery County.
The other Maryland municipalities that already let non-citizens vote in local elections are Takoma Park, Somerset, Glen Echo, Martin’s Additions (all in Montgomery County); and also Hyattsville and Mt. Rainier (both of them are in Prince Georges County). Montgomery and Princes Georges Counties are the two Maryland counties that border Washington, D.C. Thanks to Michael Drucker for the news.