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 the city 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).
Paul had an exceptionally perilous path just to visit Derbe for the first time!
In Pisidian Antioch his effective and succesful preaching so angered the Jews that they got those in power to expel him from the city (Acts 13:45 - 50). He then, travelling east, goes to Iconium. Once again, his evangelistic success so infuriates Jews in the city that they assault him with plans to stone him to death (14:1 - 6). Fleeing again, he and Barnabas make it to Lystra.
Paul's healing of a cripple man in Lystra initially brings adulation from the city. Jews from Antioch and Iconium, however, soon show up and stir up the people against the two apostles. He is then literally stoned to death and dragged outside the city!
Then Jews from Antioch and Iconium came there; and after persuading the multitudes, they stoned Paul and dragged him outside the city, supposing that he was dead (Acts 14:19).
God, who likely had to resurrect Paul back to life to continue his ministry, inspires him to finally make it to Derbe. The city provides a far less tumultuous evangelistic atmosphere than the previous areas he and Barnabas visited. In fact, it is the only location in Galatia where Paul, during his first journey, was able to preach with relative peace and start a new church (Acts 14:20 - 21, see also 2Timothy 3:10 - 11).