Ajdovščina is the largest settlement in the Vipava Valley. In the 3rd century there was a Roman settlement Ad Fluvium Frigidum (‘by cold water’). Along Hubelj was the old border between Goriška and Kranjska. The place gained market rights in 1507. Today it is the economic and cultural center of the Vipava Valley.
The first mention of Ajdovščina dates back to around 2000 BC. In the Bronze and Iron Ages, a fortified settlement stood on the nearby hill Gradišče. In the early period of the Roman Empire, after the road from Aquileia to Emona was built, a small post and freight station, known as the manor Fluvio Frigido, stood on the site of today's Ajdovščina.
In the late 3rd and early 4th centuries, the Roman Empire built the Claustra Alpium Iuliarum fortification system, which runs from the Kvarner Bay, present-day Rijeka to Cheddar in present-day Italy. Its center was the fortress Castra or Castrum ad Fluvio Frigido, the remains of which are still visible today in Ajdovščina.
Despite the fact that the Italian border is less than 20 km away and that Ajdovščina was under Italian administration from 1918 to 1947, the architecture of the city is not reminiscent of a typical Italian city. A strong bora wind would damage the usual Italian house construction. Thus, the population took over and changed the classical karst architecture for their own needs; for example, by laying stones on roofs to weigh down roof tiles from strong winds.
The main road Vipava - Nova Gorica leads through Ajdovšina. The main road Ajdovščina-Col-Črni Vrh leads to the 500 m higher settlement Col.
Slovenian expressionist painter and photographer Veno Pilon (1896-1970) was born in Ajdovščina. The main road Vipava - Nova Gorica leads through Ajdovšina. The main road Ajdovščina-Col-Črni Vrh leads to the 500 m higher settlement Col.