Namely, the municipality and the town of Kostajnica are connected with the main road M-14 Bihac-Kostajnica-Gradiska, which in Kostajnica connects to the main and regional roads in Republic of Croatia (in Hrvatska Kostajnica). Regional road R-475 Kostajnica-Prijedor is especially important. The municipality also possesses developed local road network which is not entirely completed, but the process of modernization is in progress.
Also, the municipality is situated along the railway line Zagreb-Sisak-Banja Luka, which enters the municipality in Grdanovac. The municipality has developed telephone network, both land-line and mobile.
Apart from the Una river, the municipality is intersected by the rivulets of Strigova, Tavija and number of creeks out of which the most important are Stidena, Bubnjarica, Petrijicica, Skakavac, Durica potok and others.
Geographically, the municipality is located at 100-407 m above the sea level which is very favourable for certain activities. Climate is mild moderately continental and atmospheric precipitation is equally distributed over a year. One fourth of the municipality is located in plains and other part is hilly areas. Around 30% of the municipality are forests, especially beech and other deciduous trees that cover two the most important locations – Pastirevo i Balj. Very valuable are chestnut forests that are rarely found in the entire Bosnia and Herzegovina territory.
The centre of the municipality is located in the town of Kostajnica which is a economy – industry, culture-education, sport and administration centre of the entire municipality and the region. 4000 people live in the town. The municipality has population of 9000 people. A large area that relies on the Kostajnica town has an approximate area of 300-400km2 and population of approximately 20000 people.