Mission Hill and Jamaica Plain: Two neighborhoods in search of a border

Add border historian Charles Swift to the list of people who wish real-estate brokers would stop conflating neighborhoods. Specifically, stop calling Mission Hill part of Jamaica Plain:

... First, Mission Hill is not part of Jamaica Plain. Look at the two names. One has "hill" in it, the other "plain". These two geographic features are mutually exclusive. Jamaica Plain was that part of Roxbury which flattened out from Fort Hill and Mission Hill, from the Stony Brook over to Jamaica Pond. ...

However, he adds that Jamaica Plain is, and always will be, part of Roxbury.