Catharina Meessen (born 1913 or 1914) is a centenarian who is the last-surviving citizen of Neutral Moresnet, a small country in central-western Europe that was jointly administered by the United Kingdom of the Netherlands (later as Belgium) and the Kingdom of Prussia from 1816 until 1920, when it was annexed by Belgium as part of the Treaty of Versailles.
The eldest of 10 children, Meessen was born in Neutral Moresnet in 1913 or 1914. She has lived in the same house in the former territory - which today is known as the Belgian municipality of Kelmis - since 1945. She lives together with her daughter Anne. She was visited by Mayor Louis Goebbels to celebrate her 100th birthday.
On 26 October 2016, at age 102, she became the last-surviving citizen of the former territory upon the death of fellow citizen Alwine Hackens-Paffen. Unlike Hackens-Paffen, Anne said in an interview that her mother never talks about Neutral Moresnet and 'does not find it interesting' that she is the last-surviving citizen. Meessen has declined to give interviews.<ref name="Trouw" />