When the Saybrook Platform went into operation, the minister then living within the present limits of Middlesex Association belonged to the Association in the counties of New London and Hartford. They and their churches were also connected with the Consociation in those counties. The erection of Middlesex county in 1785, consisting of towns taken from the counties of New London and Hartford, opened the way for an ecclesiastical change. Accordingly, at a meeting of the members of the Western Association of New London, living within the limits of the new county, held October 2d, 1787, a resolution was passed, That, whereas the Honorable General Assembly of this state have formed a new county by the Name of Middlesex, it becomes expedient, according to the Platform, that an Association and Consociation should be formed consisting of ministers and churches within the county. These bodies were accordingly formed by the ministers and churches of Saybrook and Killingworth, (six churches and six pastors,) giving full liberty to those of Hartford South within the limits of the new county to retain their former connection or join the new body, as they might judge expedient; and also agreeing to receive the pastor and churches of Lyme according to their desire.
Agreeable to these provisions, the ministers of Haddam, Middle Haddam, East Hampton, Westchester in Colchester, East Haddam and Lyme and also the churches at Deep River and Essex, since formed, united with the Association. The churches and ministers of Middletown and Portland, as a matter of convenience, retain their connection with Hartford South. Durham, annexed to the county in 1799, for the same reason retains its connection with New Haven East.
The rules and usages of this body are much like those of the other Associations of the State.