Through the rolling hills of the Township of Cavan Monaghan lies the small community of Millbrook, with an approximate population of 1600. Millbrook began in 1816 with the construction of the first saw mill by John Deyell. John migrated from Ireland and landed in a stream filled area with plenty of forest, which made this an ideal area for construction of a saw mill. The original mill once stood at the current site of Needler's Mill which can be found today at 1 Needler`s Lane. Prior to the 1880's, Millbrook blossomed as an agriculture rich community to an astounding 1700 inhabitants. The decade following 1880 saw nearly half the population of Millbrook move to Manitoba and Western Canada with the extension of the Canadian Pacific Railway and new settlement opportunities. It has taken almost a century for Millbrook to recover the population lost.

Millbrook is unique, culturally diverse and is rich in heritage. It boasts an amazing 45 historically designated buildings. Millbrook has the most historically designated buildings, per capita, then any other town in Ontario and recently in Canada. Downtown Millbrook has some of the most prominent historic buildings in the area. In 1875, a tragic fire known as The Great Fire, destroyed most of Millbrook's buildings along Tupper and King Street.

This fire forced the community to rebuild with a variety of different architectural styles. Some of the more prominent buildings in the area were built in the late 1880's to the early 1900's. In 1881, construction of the Old Fire Hall, located on Hay Street, began in a rare Tuscan style with a tower. It was designed to allow for the drying of fire hoses on the building. In 1889, the Old Millbrook School, located on Dufferin Street, was constructed on the top of a hill overlooking the community. It was constructed in the 19th century school style. This location is presumed to be an old native campsite. One of the most notable historical buildings in Millbrook is Needler's Mill. Located on Needler's Lane, it officially made its debut in 1909 as it replaced two previous mills. The mill was moved from Cedar Valley and was restored, by citizens from the area, in 1982. It currently resides as one of the most important heritage buildings in Millbrook.

In 1974, the Township of Cavan and the Village of Millbrook became part of the Greater Peterborough County. In 1998, North Monaghan Township, Cavan Township and the Village of Millbrook amalgamated to become the Township of Cavan-Millbrook-North Monaghan. In 2007, the Township changed its name again to the Township of Cavan Monaghan. Millbrook provides many services to those living in the area.