Attendorn is a German town in the Olpe district in North Rhine-Westphalia. As of 2019 it had a population of 24,264. The town's location was fav…Attendorn is a German town in the Olpe district in North Rhine-Westphalia. As of 2019 it had a population of 24,264. The town's location was favoured by the good climate in the Attendorn-Elsper Limestone Double Basin, the fruitful soil and favourable transport potential, and was already attracting people in prehistoric times. Heavier settlement, however, can be traced only as far back as the Middle Ages.