The eastern Asia Minor city of Derbe, along with Iconium and Lystra, was located in the southern part of the Roman province of Galatia. The residents of Derbe spoke a different language from those located north of Iconium.
Derbe's location in the far eastern part of the province made it the last city, on a road that heads east, that was within distinctively Roman territory. Commerce and trade entering the city and going west were required to pay Roman customs fees.
The Apostle Paul visited Derbe during his first, second and third missionary journeys. It was one of four cities in the eastern part of Asia Minor (not including his hometown of Tarsus) he visited at least three times during his ministry. Derbe was also hometown of a man named Gaius, who was one of several people who accompanied him on the last half of his third journey (Acts 20:4).
Paul was able to travel relatively easy to the city, during his first journey, using the then roughly fifty-year old Roman paved road called the Via Sebaste.
The Via Sebaste ran through Pisidian Antioch to Iconium, a distance of about 93 miles (150 kilometers). It then ran from Iconium to Lystra, a distance of 18.5 miles (30 kilometers). From Lystra he traveled on an unpaved track of the road about 62 miles (100 kilometers) to Derbe (Book of Acts in Its Graeco-Roman Setting, Volume 2, by Gill and Gempf, Chapter 10).
Derbe, a city whose first Christian church was founded by Paul, was a far less tumultuous destination for preaching the gospel than other locations in Galatia. It was the only location in Galatia, during his first journey, where he and Barnabas (as Scripture suggests), were able to preach the gospel in peace (Acts 14:20 - 21, see also 2Timothy 3:10 - 11).
Paul, prior to coming to Derbe, was expelled from Antioch by civic leaders (Acts 13:50), then threatened with assault and the possibility of being stoned in Iconium (14:1 - 6), then ACTUALLY stoned to death in Lystra and dragged outside the city (verses 19 - 20)!