Among the archives in the custody of the Town Council there is a copy, made in the fifteenth century, of a charter granted in 1262 by John Fitzalan, Lord of Arundel. By this charter John granted to the Burgesses of Oswestry "full and free power and authority to ordain, make and conclude among themselves praiseworthy ordinances and agreements for their betterment and benefit" (translation from the Latin). This is the earliest indication we have of a group of people in Oswestry working together for the common good of the Town. Later royal charters, of Richard II in 1398, and Henry IV in 1407, set out in more detail the rights and privileges to be enjoyed by the Burgesses, and the extent of their jurisdiction. By 1582 disputes and misunderstandings had arisen in the Burgesses' administration of local affairs, and constitutions were agreed that year "for the good and quiet government" of the Town. Twenty-five Burgesses were to be elected to the Common Council, who, together with the two Bailiffs they elected, would "doe and execute in everie thing according toe their best skill all that which by the said commen Counsell shallbe from tyme to tyme determyned". It was perhaps inevitable that there would be disagreements between the Burgesses and the Lord of Oswestry about the liberties enjoyed by the former and the privileges claimed by the latter, and the doubts and ambiguities in the interpretation of previous documents resulted in the granting of a new charter by James I in 1617. Under this charter Oswestry was to be a free borough, its affairs to be administered by the Bailiffs and Burgesses, with the right to hold land, a common seal, a Guildhall, authority to make laws and impose fines. This charter remained in force for over half a century.
In 1673 the Lord of Oswestry, the Bailiffs and Burgesses petitioned for a new charter, giving as grounds for the petition the loyalty of the Town to the King during the Civil Wars of the mid -seventeenth century, and the damage suffered at the hands of the Roundheads. In the new charter, in place of the Bailiffs and twenty-five Burgesses, there was to be a Mayor, twelve Aldermen and fifteen Common Councilmen. A Town Clerk was appointed, the nomination to that office to be in future the prerogative of the Lord of Oswestry.
The 1674 charter remained in force until local government nation-wide was reorganised under the Municipal Corporations Act of 1835. Under this Act the administration of Town affairs was placed in the hands of the Mayor, six Aldermen and eighteen Councillors. Whereas under the charters the Common Councilmen had been elected by the Common Council itself, the Councillors were now elected by the ratepayers of the Town. The Mayor and Aldermen continued to be elected by the Council. The Town Clerk was appointed by the Council, as is the case today. The new style Council was a major force in developments in Oswestry in the next 130 years. Health and housing, water and electricity, the fire brigade, allotments, markets, parks, street works were all under its administration, some of these responsibilities being eventually lost in subsequent legislative changes.
In 1967 a reorganisation of local government in Shropshire resulted in the creation of the Rural Borough of Oswestry. Some of the functions of the old Borough Council were transferred to Oswestry Rural District Council, leaving the Rural Borough Council to operate in much the same way as a traditional parish council, but retaining responsibility for markets, car parks, and parks (until 1972) and open spaces in the Town. In the major reorganisation of local government in 1974 the Rural Borough Council became the Town Council, with sixteen instead of eighteen Councillors from 1975. Despite the reduction in powers in 1967 the Council still plays a major role in all aspects of the life of the community, striving, as did the early Burgesses, for the "betterment and benefit" of the Townspeople.