Geilenkirchen is a small city in the Heinsberg district of North Rhine-Westphalia, Germany. The city has a population of around 27,000 people and is located near the German-Dutch border. Geilenkirchen is known for its historic buildings, including the St. Marien Church and the Castle Trips, which dates back to the 12th century. It is also home to the NATO Air Base Geilenkirchen. The city's economy is mainly focused on agriculture and small businesses. Geilenkirchen offers a range of recreational activities, such as hiking and cycling in the surrounding countryside.