They are mostly confined to the Elbe and Danube basins, in modern-day Germany, Austria, Czech Republic, Slovakia, as well as the adjacent parts of Hungary and Poland, in a stretch of Central European land some 800 km (500 mi) across.
The distribution of these structures seems to suggest a spread from the middle Danube (southern Slovakia and western Hungary) towards the west (Lower Austria, Lower Bavaria) along the Danube and to the northwest (Moravia, Bohemia, Saxony-Anhalt) following the Elbe.
They precede the comparable circular earthwork or timber enclosures known from Great Britain and Ireland, constructed much later during c. 3000 to 1000 BC (late Neolithic to Bronze Age).
But, by contrast to the long lifetime of the "Megalithic" culture, the time window during which the neolithic Roundels were in use is surprisingly narrow, lasting only for about 200–300 years (roughly 49th to 47th centuries BC).
[3] The earliest roundel to be described was the one at Krpy (Kropáčova Vrutice), Bohemia, by Woldřich 1886, but it was only with systematic aerial survey in the 1980s and the 1990s that their ubiquity in the region became apparent.