Heres a pretty interesting article about Roxburys boundaries.
“The settlement dictated that the land southeast of where Massachusetts Avenue. meets the Charles River would remain as part of Roxbury. Run a line from the boundary marker by Ramsey Park to that point on the Charles, and it’s clear that Northeastern University, the Museum of Fine Arts and much of the Fenway sit well within the historical boundaries of Roxbury. The Longwood Medical area and Harvard’s Medical School and School of Public Health also sit in Roxbury.
But ever since Roxbury was incorporated into Boston in 1868, perceptions of the neighborhood’s boundaries have been in flux.
The Parker Hill section of Roxbury became dominated by Irish immigrants who began calling the area Mission Hill, after the Roman Catholic basilica that was built there.
Mission Hill residents did not begin to reclaim the Roxbury name until the 1970s when tenants facing displacement by a Harvard University land-grab on South Huntington Avenue adopted the name Roxbury Tenants of Harvard…”
https://www.baystatebanner.com/2014/02/19/roxburys-boundaries-buried-in-town-history/