The Emerald Necklace consists of a dozen linked green 'jewels', its parks parks and parkways, which are almost contiguous. The first three - Boston Common (1634, 50 acres), the Boston Public Garden (1837, 24 acres) and the Commonwealth Avenue Mall (1865, 8.7 acres) - already existed when Olmsted was first consulted in 1875 by the Boston Parks commissioners on possible public park sites within the city. But it was his idea to link the existing and proposed parks together into one continuous greenway or Green Ribbon.
The Necklace currently comprises half of Boston's park acerage and half of the city's population of over a half million live within its watershed. But, although few people know it, a major part of it is missing. Looking at a the map of the Emerald Necklace as it now exists, you'll notice that its shape is a lot more like a dogleg. The missing link that would have completed the Necklace was what Olmsted called the Dorchesterway in his master plan.
The Dorchesterway was to be a linear park, similar to the Commonwealth Avenue Mall, running from Franklin Park down Columbia Road in Dorchester to the Dorchester Marine Park, then continuing along the harbor via the Strandway (now William J. Day Boulevard) to Castle Island at Pleasure Bay in South Boston. This part of the plan was never implemented because Columbia Road was already very densely developed by the late 1800's. Some form of this plan may eventually come into being, which might additionally include a link from Castle Island back to Boston Common to truly complete the Necklace.
