While the municipality of Finnentrop didn't come into being before 1 July 1969, the history of the constituing villages dates back from the Middle Ages. In 1162 Lenhausen and Rönkhausen were mentioned for the first time. Until 13 July 1908, the place now known as Finnentrop had three names: Habbecke, Neubrücke (“Newbridge”) and, once the Ruhr-Sieg railway was built, Bahnhof Finnentrop (“Finnentrop Railway Station”). Neubrücke consisted of only one building at the forks of Bigge and Lenne (Reuters Haus, first mentioned in 1847). The “new bridge” seems to have already been built by 1847, as the “Reuter” had to charge tolls.
The new municipality was cobbled together in 1969 from parts of the old Amt of Serkenrode (Meschede district), the communities of Schliprüthen and Oedingen and parts of Attendorn-Land and Helden. This restructuring also saw the community pass from Meschede district (which was abolished in 1974) to Olpe district. The community’s name is drawn from the original centre of Finnentrop lying a few hundred metres up the Bigge, and now known as Altfinnentrop (“alt” is German for “old”). The ending —trop comes from trop or torp, meaning “village”. The High German word Dorf is a cognate, as is the English word thorpe.
The municipal arms bear a rose under a wavy chevron. The rose stands for the Lords of Finnentrop (von Vinnentrop) and comes down from the year 1358. The chevron stands for the two rivers, the Bigge and the Lenne, which merge in the community. The colour green refers to the great swathes of greenery in the municipal area.