The trace of Avsar Turkmens, one of the most important tribes of Oghuz Turkmens, around Kastamonu has been investigated at this study. Firstly, some information about Oghuz and Avsar Turkmens' coming to Kastamonu has been given. Then, some results about settlement of Avsar Turkmens in Kastamonu have been reached by investigating location names related to Avsar Turkmens. Also, some determination has been found by using the names of Avsar oba, clans and tribes. After 1071 Malazgirt Victory, Turkish invasion had been towards the Byzantine border from Eastern Anatolia region. It is likely that some of the Oghuz tribes tend to the west, had used line of Kastamonu. Oghuz tribes had given the names of their own oba, clans and tribes to the country they hold. So, they provided Turkification of Kastamonu around as well as all Anatolia. According to records, in Kastamonu Sanjak, in 16th century there were 9 residential areas which named as Avsar (Afsar). It is a very interesting founding that in this century, the most common settlement names in Kastamonu Sanjak belong to Avsar (Afsar) in Oghuz tribes. However, today settlements named Avsar in Kastamonu decreased to 6. In conclusion; many trace and information about Avsar Turkmens around Kastamonu has been reached. Especially this trace has been determinate more in the southern part of Kastamonu.