In the beginning of 2019, the Danish Government, the Danish People´s Party and the Social Democrats decided to erect a wild boar fence along the Danish-German border. This was a part of the solution to stop the invasion of wild boars migrating into Denmark, which could bring the much-feared African Swine Fever into Danish territory and as a consequence cause an estimated annual loss of 11 billion DKK and risk 33.000 jobs within the Pig Industry. This measure generated a lot of arguments for and against the fence on both sides of the border. In this thesis, I aim at answering: On what grounds was the Danish wild boar fence between Denmark and Germany erected, and how does this reflect broader discussions about borders and illegitimate flows? For answering this, I have chosen to draw on two methods; the Case Study method and document analysis as well as two analytical frameworks; an object-oriented and historic framework by Nasser Abourahme and Securitization theory by the Copenhagen School. Additionally, I have also chosen to utilize literature concerning border-, territoriality- and mobility research by Lisa Malkki and Wendy Brown etc. The conclusion of this investigation is that the long history of physical barriers, border controlling measures and the negative consequences of an invisible unprotected border between Denmark and Germany have conditioned the erection of the wild boar fence. The erection of the fence was successfully legitimized and justified by two grounds. The fence protected the Pig Industry and more generally Denmark against the migration of potentially ASF infected wild boars as well as protected the Danish society from the threat of illegal migrants and refugees. In addition to this, I have revealed that the wild boar fence shares four common features with other recent proliferated barriers in the world. First, its multifunctional purposes. Second, its inefficiency and lack of evidence towards its primary purpose. Third, the fact that it targets transnational flows. Four, some of the symbolic purposes of physical barriers, where the primary is to keep something unwanted out of its territory and the nation-states´ ambition of enhancing the collective and individual identity of its people.