Council office, and units were "recommended to be numbered according to the District in which they reside". However, in 1975 the BSA changed its policy and authorized individual councils to provide local numbers as they saw fit. In 1967 the BSA expanded its council numbers above 639, when it allowed the Greater New York Councils, consisting of the five boroughs in New York City along with the City itself their own Council number (NYC, #640; then in alphabetical order, Bronx, Brooklyn, Manhattan, Queens, and Staten Island). In 1971, the BSA started a new row of Council numbers starting with the Rainbow Council in Morris, Illinois (#702). In 1976, the BSA allowed the Boston Council and the other councils surrounding Boston (Cambridge, Minuteman, and North Bay) to form a "consolidated council" similar to the way that New York City and the five boroughs were organized. This consolidated council was designated as council 850. However, the effort failed and the councils split again in 1979; eventually the Boston, Cambridge and Minuteman merged into the Boston Minuteman Council, while North Bay became part of the Yankee Clipper, until Boston Minuteman and Yankee Clipper merged to become the Spirit of Adventure Council. Councils by size The BSA categorizes councils by size. Currently, there are five categories of council: (1) Mega Councils (the top 20 local Councils by youth membership and units), (2) Metro Councils (the next 20 or so local Councils), (3) Medium Councils, (4) Small Market Councils, and (5) Community Councils, which are the smallest, normally taking in large neighborhoods or one or two cities. Geographically, a council like the Montana Council serving most of the state of Montana, or the Midnight Sun Council serving the interior of Alaska have the largest coverage areas, but relatively few Scouts. Council size may also fluctuate because of mergers, like the repeated merger and splitting of the Monterey Bay Area Council (#025) and the Santa Clara County Council (#055). Largest councils Smallest councils The Piedmont Council is the last small council after the Alameda Council and Cambridge Council merged with larger councils. Unique councils The Greater New York Councils is the only council in the nation divided into smaller councils. It is divided into five borough councils with each led by a field director and one or more district directors or district executives. Conversely, due to Scouting population and geographic distance, the Utah National Parks Council