In the year 1767, the township of Coleraine was one of the original five townships formed within Cumberland County's frontier region. It stretched from Evitts Mountain in the west to the eastern slope of the mountain range composed of Town Hill in the south and Rays Hill in the north. It stretched from Johns Branch of the Raystown Branch of the Juniata River and Harbor Mountain in the north to the provincial boundary line with Maryland in the south. Providence Township was formed out of the northern part of Coleraine in 1783.
In 1840, Monroe Township was formed out of the southern half of Providence Township and a portion of Southampton Township. The boundary line defining the north boundary of Monroe Township was a surveyed line stretching from the southeast, at a point on Rays Hill to the northwest, at a point on Tussey Mountain.
In November 1838, a number of inhabitants of Southampton and Providence Townships petitioned the Court of Quarter Sessions for a new township to be formed out of portions of the two of them. The petition was continued to the April 1839 session. The Court finally responded to the request on 31 August 1839:
At a Court of Quarter Sessions of the Peace held at Bedford in and for Said County of Bedford on the 31st day of August A.D. 1839 before the Judges of the Same Court. Upon the Petition of Sundry Inhabitants of the Townships of Southampton and Providence in Said County being read at November Sessions last and at January Sessions last the First of which Setting forth "that from the large bounds of Said Township your petitioners labour under great inconvenience in their Township affairs, and as the Legislature has given a new Election District in the East ends of Said Townships, which has eased us of some inconvenience, but many yet remains, for the removal of which we pray the Court to appoint proper persons to view and lay out a new Township to be called Hemson as follows commencing at or near Samel Layton and running a W. Course so far as to include the house of Jacob Millers, thence a due South course to the Maryland line, thence round the lines of the East end of the Township of Southampton to the place of Beginning." And the Second of which Setting forth "that they labour under great inconvenience on account of the extent of the said Township and on account of the distance which they must necessarily travel in order to attend the Election for township officers and praying the Court to erect a new Township out of parts of Southampton and Providence Townships to by called 'Monroe' according to the following lines and boundaries, Beginning at a point of the Top of Tusseys Mountain in Providence Township so as to include the house of Joseph and John Sparks by running a straight line from thence to Rays Hill and including likewise the house of James Layton at or near Said Ray's hill thence running a South course to a point at or near the house of George Blankley Esq so as to include Said house, thence running a westwardly course to a point at or near Mill's Gap thence along said Tusseys mountain to the place of beginning." Whereupon it is considered by the Court and ordered that that the former Report or Reports of the Commissioners be and they are thereby Set aside and that James Piper Esq Abraham Ritchey and John Folck Junior be and they are hereby appointed Commissioners to view and examine the lines and boundaries of the Said Township prayed for in the first and subsequent petitions and consider the propriety of the erections of a new Township and give their opinions of the same and make report which of the two plans (if either) ought to lie adopted to the next Court of Quarter Sessions of the Peace, according to the act of Assembly.
As can be seen from the foregoing, the first option was to call the new township "Hemson." The commissioners returned their report on 18 November 1839 stating that they chose the second option which was to name the new township 'Monroe.'
The order was continued until the February 1840 session and finally on 25 April 1840, "The court Confirmed the Report of the Commissioners and Order the Township to be erected and to be called Monroe."
The township was named in honor of President James Monroe, the fifth President of the United States of America (from 1817 to 1821 and 1821 to 1825).
